Political and cultural background prior to Midian's birth.
About the year 1800 BC when Abraham was about seventy-five years old, climatic conditions and migrations of foreigners in the Levant continuously forced local peoples to seek sustenance elsewhere.
Genesis 12:10 And there was a famine in the land: and Abram went down into Egypt to sojourn there; for the famine was grievous in the land. 
For centuries the Egyptians fought to keep the Semitic Canaanites and Syrians out of Egypt proper but allowed them to settle in the Nile delta. To monitor and regulate these settlements they established a string of military outposts in Sinai and along the coast of the eastern Mediterranean, exacting tribute from the leaders of the many small local tribes. They looked on them with contempt as uncivilized nomads and cattle herders. Yet in the biblical accounts of the time in which Abraham lived there is no mention at all of an Egyptian presence in Canaan. A great change had occurred in the Egyptian kingdom.
"These tribal leaders, pushed southward by a people called the Hurrians on the one hand and lured by the rich pasture land and agricultural land of Egypt on the other, were arriving at a time of great political instability in Egypt - the Middle Kingdom had come to an end and the country was being ruled by parallel dynasties of weak rulers. It was not hard for these displaced leaders to take power in this disorganized situation. It doesn't seem that they encountered much by way of coordinated resistance, perhaps because of the presence of a large foreign population already within Egypt, as indicated by the 'Brooklyn Papyrus' of the 13th dynasty which lists no less than forty-five people of Asiatic origin who were members of the household of an upper Egyptian official."
-Peter H Blustin untitled
Tutimaeus. In his reign, for what cause I know not, a blast of God smote us; and unexpectedly from the regions of the East, invaders of obscure race marched in confidence of victory against our land. By main force they easily overpowered the rulers of the land, they then burned our cities ruthlessly, razed to the ground the temples of the gods, and treated all the natives with a cruel hostility, massacring some and leading into slavery the wives and children of others."
Josephus Flavius, translating the work of Manetho, a 3rd century BC Egyptian historian, uses the word 'obscure' for Hyksos, the term describing the 14th-17th dynasties, whose Pharaohs were Semitic. The word is derived from the Egyptian 'hekau' rulers and 'khwaswt' foreign. The victorious Semites, unable to immediately capture the Egyptian capital at Memphis, established their own in the Nile delta where they had originally settled and called it Avaris. This is the same city later called Pi-Ramesse or Raamses. It and the city of Pithom later became sites of forced labor for the Hebrews. It was at this time that worship of El and Baal were introduced to Egypt. The Hyksos were able to achieve an easy victory because of their use of the horse drawn chariot which was previously unknown in Egypt. They also introduced the institution of slavery, which had not existed here before, the Egyptians being unwilling to enslave their own people. As a result of the Semitic conquest many Egyptian and Ethiopian women and children were transported back to the invaders homelands as slaves and bond servants.
"The Hyksos and the Hebrews were racially akin. Some of the Hyksos rulers had Semitic names. Most scholars now agree that there is some connection between the Hyksos rule of Egypt and the settling of the Hebrews there. It seems reasonable to assume that the Hyksos, who themselves had traveled the caravan routes to Egypt for centuries before they finally took power there, favored other 'Apiru' [i.e. nomad, from which the term Hebrew is thought by some to have originated] groups and encouraged them to settle. When Pharaoh Amosis captured Avaris and expelled the Hyksos from Egypt, pursuing them to Palestine and opening the way to Asia and so the great age of the Egyptian empire in the 18th and 19th dynasties (the New Kingdom), the Hebrews in Egypt were left without protectors. Contemporary documents show that the Hyksos who escaped slaughter were enslaved. It is reasonable to suppose that the Hebrews, now unprotected by the Establishment, were also enslaved at this time."
-David Daiches, Moses, Man in the Wilderness
Knight and Lomas in their book "The Hiram Key" suggest that Abraham might have been considered a Hyksos, 'a desert prince' who entered Egypt around 1780 BC. His ability to enter Pharaoh's house and be treated civilly by him, when the king desired his wife Sarai, suggests that they were of the same ethnicity.
Genesis 12:15-16 The princes also of Pharaoh saw her, and commended her before Pharaoh: and the woman was taken into Pharaoh's house. And he entreated Abram well for her sake: and he had sheep, and oxen, and he asses, and maidservants, and she asses, and camels.
It is thought that it was at this time that Abraham acquired Hagar, an Egyptian bond slave, to serve his wife Sarai, he being well able to afford such.
Genesis 13:1-2 And Abraham went up out of Egypt, he and his wife, and all that he had, and Lot with him, into the south. And Abraham was very rich in cattle, in silver, and in gold.
Years later when Hagar and her son Ishmael, Abraham's firstborn, were living in the area called Paran, she had no trouble finding a wife for him that was Egyptian like herself. The population in the area continued to be ethnically and racially mixed for hundreds of years with admixtures of Egyptian, Ethiopian, Hittite, Hurrian, Mitanni, Philistine and Assyrian, each bringing with them their gods. Isaac, the son of Abraham and Sarah, took a wife from his father's family, as did his son Jacob. However Jacob's brother Esau married one of Ishmael's daughters.
The birth and times of Midian
Midian was the fourth son of Abraham born to Keturah, his third wife. When Sarah, his first wife was barren and past the age of childbearing, in order to remove the reproach of being childless, she gave her handmaiden Hagar to her husband to be his wife and bear a child for her.
Genesis 16:2-3 And Sarai said unto Abram, Behold now, the LORD hath restrained me from bearing: I pray thee, go in unto my maid; it may be that I may obtain children by her. And Abraham hearkened to the voice of Sarai. And Sarai Abram's wife took Hagar her maid the Egyptian, after Abram had dwelt ten years in the land of Canaan, and gave her to her husband Abram to be his wife.
Hagar was not Abraham's mistress or slave but a concubine with a legal standing which, by the custom of the time, he was obligated to treat as a wife and could not summarily dispose of her. When a wife gave her handmaiden to her husband for the purpose of childbearing, the child was considered an equal as an heir, as the children of the handmaidens of Leah and Rachel were. After the death of Sarah, Abraham took Keturah as his wife, along with others.
Genesis 25:1-2 Then again Abraham took a wife, and her name was Keturah. And she bare him Zimram, and Jokshan, and Medan, and Midian, and Ishbak, and Shuah.
There is no contradiction as to whether Keturah was Abraham's wife or concubine. The term concubine has more to do with Abraham's intentions than with her previous status as bond or free. Her children were not to be heirs on an equal standing as Isaac but still received a portion of Abraham's wealth. The name Keturah in Hebrew means 'incense' or the perfumed one'. Although her name is Hebrew there is nothing to indicate her origin; she was almost certainly not Canaanite, but probably an Egyptian or Ethiopian born to other of Abraham's bond servants.
Genesis 24:2-3 And Abraham said unto his eldest servant of his house, that ruled over all that he had, Put, I pray thee, thy hand under my thigh: And I will make thee swear by the LORD, the God of the earth, that thou shalt not take a wife unto my son of the daughters of the Canaanites, among whom I dwell:
Abraham had good reason to keep distant from all things Canaanite. They had corrupted all that had been passed down from their forefathers concerning the true god. The name 'El' became a generic term for god throughout the region. From the same root comes the modern Arabic Allah.
"The supreme god was El who was seen as the father of the gods and ruler of the divine assembly on the 'mountain of the gods'. El's consort and counterpart was Asherah, a marine goddess who was seen as the creator of creatures and mother of the gods. If El is portrayed as somewhat remote, his divine executive, Baal was certainly not. He represents the royal power and authority of God, and is depicted on sculptures and statuettes as a warrior god bearing spear and mace."
-Jonathan N Tubb, Canaanites
Abraham taught the knowledge of the true god to his family, so much so that even his servants worshipped as he did. Nevertheless he separated his son Isaac from his brothers who were born of foreign women.
Genesis 25:6 But unto the sons of the concubines, which Abraham had, Abraham gave gifts and sent them away from Isaac his son, while he yet lived, eastward, unto the east country.
The east country to which Midian and his brothers were sent is on the eastern shore of the Gulf of Aqaba. They and their older brother Ishmael who had settled on the other side of the gulf in Paran appear to have formed an alliance and eventually controlled the trade routes between Arabia and Egypt.  They expanded into Sinai, the Negev desert and Edom, which are north of the gulf, and to the borders of Moab, their camel caravans carrying them and their wares throughout the region. Eventually they migrated to the upper Jordan valley east of the Sea of Galilee. When Solomon expanded the borders of his kingdom to include Ezion-Geber, which is on the Gulf of Aqaba, he cut the route of the spice trade and gold trade from Arabia to Egypt. This precipitated a visit by the Queen of Sheba, a descendant of Jokshan, Midian's brother, bearing gifts and making deals.> The language of Sheba, which is in the southern part of the Arabian peninsula is Himyaritic, which survived in Yemen until the 14th century AD when it was supplanted by Arabic. Ethiopic is a branch of Himyaritic spoken in Ethiopia until the 16th century when it was supplanted by Amharic. All theses languages plus Hebrew, Aramaic and the speech of the Moabites, Amorites and Amalekites are Semitic and it was not difficult for the speaker of one to understand the speech of another from this group. The Egyptian language was not in this language family. Ethiopia and Sheba are separated by only twenty kilometers across the southern end of the Red Sea and to this day the now defunct royal house of Ethiopia claims its descent from the Queen of Sheba.
During the three hundred years following the birth of Midian the Midianites supplemented their income from trade by raiding and pillaging their neighbors, although some sought a more honest means of living by mining and working copper. The truth that Abraham had taught his children was kept alive and passed down from generation to generation despite the absence of any record of contact between the children of Midian and the children of Israel. It was during this period that the Hyksos rule was overthrown and the Egyptians re-established control of their country only to face a new enemy that was just beginning to invade their land, the Sea People, of which the Philistines were a part.
Moses and the Midianites
One day in the land of Midian after Moses had fled from Egypt he had the opportunity to help the seven daughters of the priest/prince of Midian. His name was Reuel, which means 'friend of god'. He was not the only man in the bible so named, not even the first. That distinction went to the grandson of both Ishmael and Isaac, through Esau and Ishmael's daughter Bashemath. It is difficult to think that the sons of Abraham and Isaac used the suffix 'El' in reference to the weak patron of Baal but rather to El Shaddai, the true God. The close affinity between Reuel and his descendants to the children of Israel would not be possible if they were worshippers of the Canaanite god Baal.
Exodus 2:16-21 Now the priest of Midian had seven daughters: and they came and drew water, and filled the troughs to water their father's flock. And the shepherds came and drove them away: but Moses stood up and helped them, and watered their flock. And when they came to Reuel their father, he said, How is it that ye are come so soon to day? And they said, An Egyptian delivered us out of the hand of the shepherds, and also drew water enough for us, and watered the flock. And he said unto his daughters, And where is he? why is it that ye have left the man? call him, that he may eat bread. And Moses was content to dwell with the man: and he gave Moses Zipporah his daughter.
It is plain that the name of the father of the woman that Moses was to marry is Reuel although a variant spelling occurs later.
Numbers 10:29a And Moses said unto Hobab, the son of Raguel the Midianite, Moses' father in law….
The term 'father in law' though correctly supplied here is not a valid translation of the Hebrew word chathan. This word may be applied to any, even unspecified, relationships through marriage, and is so used three times and even once for mother in law.
The daughters regarded Moses as an Egyptian when they told their father of the help he had given them, no doubt only a generality because of his speech and dress with which they would have been familiar because of their ancestry and their trade with Egypt and Ethiopia. In the same fashion Moses' sister Miriam called Zipporah an Ethiopian (Heb. Cushite) which scholars suppose was because her complexion was dark like the Ethiopians and Shebans.
As noted above, Hobab was the son of Reuel. There is no justification to assume that Jethro was Reuel and not also his son. In every instance that Jethro is mentioned as the father in law of Moses, the text reads the chathan (in law) indicating some affinity by marriage. A weak argument has been made to the effect that the man's name was Reuel but his title was 'Jethro', which means 'excellence' or 'his Excellency'. Every place the name Jethro appears it is in a narrative; no body ever calls him Jethro. In one place when his name is spoken it is Jethro himself who speaks it when he arrived at the Israelite camp.
Exodus 18:6 And he said unto Moses, I thy father in law (brother in law) Jethro am come unto thee, and thy wife, and her two sons with her.
It is unlikely that he was saying "I thy father in law, his Excellency . . ."
"The different names by which Moses' father in law seems to be called create a difficulty, though not of a serious nature. It seems best to regard Raguel as the father-in-law of Moses, and to suppose Jethro and Hobab to be his brothers-in-law. The Septuagint renders the Hebrew chathan (translated father-in-law in our version) by γαμβός, (gambos) which means brother-in-law and father-in-law. With this rendering-brother-in-law-all is easy. Moses marries the daughter of Raguel, priest of Midian. About forty years after this, when, we may suppose, Raguel was dead, Jethro his son succeeded him as priest, and Moses, his brother-in-law, was keeping his flocks."
-Henry M. Harman Introduction to the Study of the Holy Scriptures.
Jethro knew Moses for forty years and what he learned from him and from his father Reuel lead him to declare after this meeting when Moses returned from Egypt and recounted the events of the Exodus:
Exodus 18:11 Now I know that the LORD is greater than all gods, because he delivered the people from under the hand of the Egyptians, when they dealt arrogantly with them. Revised Standard Version
"Hobab, another brother-in-law of Moses, visits him on his journey, as we find in Numbers x29. The visit of Hobab to Moses mentioned in this last verse is evidently a different one from that described in Exod. xvii as having been made by Jethro, in company with the wife and the two sons of Moses."
-Henry M. Harman Introduction to the Study of the Holy Scriptures.
When Moses met Reuel he met a man with at least nine children. Typically at that time men did not marry young; Isaac was forty, Jacob in his seventies, Moses himself about seventy, for when he was eighty his two sons were small enough to ride with their mother on an ass. Reuel was surely older than his son in law. Other than his marriage and the birth of his two sons Moses records nothing of the events in Midian until the angel of the LORD visits him. Living with Reuel and his family he remained faithful to what he had been taught of God, expressing it in the name of his second son.
Exodus 18:4 And the name of the other was Eliezer (God of help); for the God of my father, said he, was mine help, and delivered me from the sword of Pharaoh:
Jethro the Midianite rejoiced in what Moses told him of the events in Egypt. He blessed God and offered sacrifices, and Moses and Aaron and all the elders of Israel ate bread together with him. He offered good counsel to Moses which was accepted and acted upon, but then he left to go back to his own land. The majority of the Midianites continued to be enemies of Israel. Two years later there were still some of Reuel's family traveling with Moses.
Numbers 10:29-33 And Moses said unto Hobab, the son of Raguel the Midianite, Moses' father in law, We are journeying unto the place of which the LORD said, I will give it you: come thou with us, and we will do thee good: for the LORD hath spoken good concerning Israel. And he said unto him, I will not go; but I will depart to mine own land, and to my kindred. And he said, Leave us not, I pray thee; forasmuch as thou knowest how we are to encamp in the wilderness, and thou mayest be to us instead of eyes. And it shall be, if thou go with us, yea, it shall be, that what goodness the LORD shall do unto us, the same will we do unto thee. And they departed from the mount of the LORD three days' journey: and the ark of the covenant of the LORD went before them in the three days' journey, to search out a resting place for them.
Hobab was a Kenite; the name means 'belonging to the coppersmiths'. The copper trade flourished around the city of Timna, just north of the Gulf of Aqaba. The mines were in the hills to the east of the gulf in the heart of Midian on the route from Arabia to Egypt. The Kenites as a group were no friends of Israel. Balaam prophesied of them.
Numbers 24:21-22 And he looked on the Kenites, and took up his parable, and said, Strong is thy dwellingplace, and thou puttest thy nest in a rock. Nevertheless the Kenite shall be wasted, until Asshur shall carry thee away captive.
Hobab was not like the rest of his people in order to receive such an offer of friendship and security from Moses. They needed to be believers to remain among the Israelites. Through the remaining thirty-eight years of wandering, and the entry into and conquest of the Promised Land and into the time of the Judges, they were still faithful.
Judges 1:16 And the children of the Kenite, Moses' father [brother] in law, went up out of the city of palm trees with the children of Judah into the wilderness of Judah, which lieth in the south of Arad; and they went and dwelt among the people.
There is no record in the scriptures, other than that of Reuel and his descendants, of any Midianite being a blessing to the children of Israel. All the others had left the worship of the true god and adopted the religion of the enemies of Israel - the Moabites, the Amorites, and the Amalekites. Toward the close of the forty years' wandering of the children of Israel in the wilderness, the Midianites were allied with the Moabites against the Israelites. For this reason Moses was ordered by God to punish the Midianites. He despatched against them an army of 12,000 men, under Phinehas the priest; this force defeated the Midianites and slew all their males, including their five kings, Evi, Rekem, Zur, Hur, and Reba. These five kings may have been the rulers of the five clans descended from Midian's five sons. When the returning troops brought the spoils and all the women and children to Moses he was angered.
Numbers 31:15-18 And Moses said unto them, Have ye saved all the women alive? Behold, these caused the children of Israel, through the counsel of Balaam, to commit trespass against the LORD in the matter of Peor, and there was a plague among the congregation of the LORD. Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him. But all the women children, that have not known a man by lying with him, keep alive for yourselves.
It may be noted that the five princes of Midian were later called by Joshua the dukes (appointed leaders) of Sihon, the Amorite king of Heshbon. It is possible that Sihon had previously conquered Midian and made it a vassal, and that after his death the Midianites recovered their independence. The Israelite soldiers set on fire all the cities and fortresses of the Midianites in that area. While a part of each tribe dwelt in cities and fortresses in the vicinity of Moab, another part led a nomadic life, living in tents and apparently remote from the scene of this war.
Judges 4:11 Now Heber the Kenite, which was of the children of Hobab the father [brother]in law of Moses, had severed himself from the Kenites, and pitched his tent unto the plain of Zaanaim, which is by Kedesh.
Heber's wife was Jael, who killed Sisera. Her action helped the children of Israel to prosper and to prevail against Jabin the king of Canaan.  This was so great a blessing to Israel that God chose to memorialize it in the song of Deborah and Barak.
Judges 5:24 Blessed above women shall Jael the wife of Heber the Kenite be, blessed shall she be above women in the tent.
About one hundred and thirty years after Moses defeated the Midianites in Moab they had regained strenght and were again vexing Israel. The account in the sixth and seventh chapters of Judges asserts that the Israelites suffered at the hands of the Midianites for a space of six years. The Midianites seem to have been then a powerful and independent nation; they allied themselves with the Amalekites and the Kedemites, and they oppressed the Israelites so severely that many were obliged to seek refuge in caves and strongholds; Midianite raiders destroyed crops and reduced them to extreme poverty. The allied army of Midianites and Amalekites encamped in the valley of Jezreel after having crossed the Jordan. Gideon with his army encamped by the fountain of Harod, the Midianite army being to the north of him. With 300 men Gideon succeeded in surprising and routing them, and they fled homeward across the Jordan in confusion. A point worth noting is that here only two Midianite kings, and two princes are mentioned. This would indicate that only two tribes still bore the name Midianite while the remaining three probably were destroyed, conquered or assimilated by their neighbors, including perhaps partly with the Israelites as the Kenites were.
Judges 8:28 Thus was Midian subdued before the children of Israel, so that they lifted up their heads no more. And the country was in quietness forty years in the days of Gideon.
Eventually the majority of the Kenites drifted away from the Israelites, settling among Israel's enemies. Their separation from the main body of Midianites was never complete. They were with them and the Moabites in the time of Balaam when Moses smote them. They were with the Amalekites when Samuel gave God's instructions to King Saul to utterly destroy them. On the eve of Saul's attack God's grace spared the Kenites.
1 Samuel 15:6 And Saul said unto the Kenites, Go, depart, get you down from among the Amalekites, lest I destroy you with them: for ye shewed kindness to all the children of Israel, when they came up out of Egypt. So the Kenites departed from among the Amalekites.
Yet when David was king they were counted as an enemy and their city was looted. And still a remnant chose to believe the god of Israel. The book of 1Chronicles lists four men, Kenites, the sons of Hemeth, the father of the house of Rechab. Two hundred years after David it was Jehonadab the son of Rechab the Kenite who met Jehu and together they tricked the worshippers of Baal and slew them to a man.  Another two hundred and fifty years later when Jehoiakim was the king of Judah there were still some of this branch of Abraham's family who remained faithful to the teaching of their fathers concerning the true God.
Jeremiah 35:18-19 And Jeremiah said unto the house of the Rechabites, Thus saith the LORD of hosts, the God of Israel; Because ye have obeyed the commandment of Jonadab your father, and kept all his precepts, and done according unto all that he hath commanded you: Therefore thus saith the LORD of hosts, the God of Israel; Jonadab the son of Rechab shall not want a man to stand before me for ever.
After more than a thousand years of Midian's descendants being in contact with and learning from God's people, although never quite making a sustained commitment as a group, the persistence of a faithful few who could see the blessings that the God of Israel bestowed on His people, separated themselves from their kinsmen to follow the truth. This resulted in the tremendous promise of God as spoken forth by Jeremiah. The last son of Midian who had not joined his heart with the believers was swept away to be lost forever in the sea of peoples that were overrun by the Babylonians just twenty years later. 
 All scripture is quoted from the King James Version unless noted otherwise.
 Deuteronomy 21:10-14
 Genesis 24:52
 EW Bullinger, The Companion Bible, note on Judges 8:24,
 1 Kings 10:13-15
 1 Kings 3:1, 2 Chronicles 18:1, Ezra 9:14 (all affinity)
 Deuteronomy 27:23
 Numbers 12:1
 Exodus 4:20
 Numbers 25:17
 Joshua 13:21
 Judges 4:22-24
 Numbers 31:7ff
 1 Samuel 30:26,29
 1 Chronicles 2:55
2 Kings 10:15ff
 Habakkuk 3:7