By the start of the seventeenth century, the region we today call the Midwest was almost entirely inhabited by a wide range of Algonquian tribes who survived via a combination of agriculture, hunting, and gathering, moving from time to time as soils became less fertile and game was depleted. Formerly the territories of the Siouan peoples, climate change caused famines and warfare in the fifteenth century had weakened them to the point that the Algonquian began to migrate into the region from the east and north, drawn in part by the opportunity of new territories to claim and by the threat of the Iroquoian peoples, who were expanding from the St. Lawrence River. The pace of this conquest was significantly sped in the middle of the sixteenth century, when a pandemic of Old World diseases swept north, killing two-thirds or more of the Siouan. Resulting in a rapid expansion of the less affected Algonquian who largely drove the Siouan west of the Mississippi River by the end of the century.
When Europeans first began arriving along the Atlantic Coast, the Algonquian tribes of the Midwest were largely unaffected, distant as they were. Aside from a few French explorers and Catholic missionaries who began appearing along the shores of the Great Lakes in the 1630s, the Europeans were little more than stories that made their way over the Appalachians in a distorting game of telephone. Unfortunately, not having significant contact with the Europeans did little to protect the Midwest Algonquian. In the 1630s and 1640s, an epidemic of measles swept its way westward, spread along established trade routes, killing around half of the natives in its path, disrupting the societal and cultural foundations of the once prosperous tribes. Lacking knowledge of how diseases spread, it was likely seen as an evil portent and a lack of favor from the gods, something that was little helped by what happened next.
Beginning in the 1650s, raiding parties from the Iroquois Confederacy began attacking the easternmost Midwest Algonquian tribes in the Ohio Country, the most dominant of which were the Shawnee. Iroquois raiding parties were trying to secure beaver and captives, the former to trade with the Europeans and the latter to bolster their numbers. Thanks to the Iroquois being armed with muskets by the Dutch, these attacks were devastating. Unable to defend themselves, the Algonquian fled west and south. However, the Iroquois had no interest in settling their newly conquered territory. Not only did they lack sufficient numbers to do so, all they really wanted was to secure valuable supplies of beaver to trade to the Dutch. As a result, large portions of the Ohio Country became almost entirely depopulated by 1660. Not content, the Iroquois raiding parties began moving further west into what is today Michigan and Indiana, causing further devastation as they went.
The Iroquois invasion caused what can best be described as a refugee crisis which rippled its way westward. Tribes fleeing Iroquois attacks moved into the territories of their neighbors, resulting in a depletion of available food supplies, which in turn led to famine and conflict, which in turn led to further movement westward. These conflicts and famines depleted numbers, which made it more difficult for tribes to fight off Iroquois raids, which exacerbated an already increasingly chaotic situation. As a result, some tribes began to form alliances for mutual defense from both the Iroquois and the Algonquian refugees, the most powerful being the Illinois Confederacy which was made up of twelve of the most powerful tribes in the Illinois Country. As a result, the weaker tribes were forced north towards Wisconsin, south towards Kentucky, or further west across the Mississippi River. This in turn put them into conflict with the less numerous Siouan peoples, who in turn were forced to flee into less fertile lands bordering the Great Plains, or in the case of many weaker tribes, out onto the Plains themselves. The two most prominent of these Siouan tribes were the Sioux who moved into Minnesota and the Osage who moved into Missouri. As for the scattered and sparse Numic peoples who inhabited the Plains at the time, they were pretty well fucked.
Luckily, the Iroquois raids halted for a time by the end of the 1660s thanks to the Dutch losing their colony, cutting the Iroquois off from their primary supplier of muskets and powder. However, it was a short respite, a new devastating pandemic of Old World diseases swept its way westward in the 1670s, followed by a renewal of raids by the Iroquois, who now being armed by the English, began regularly raiding nearly to the Mississippi River. To add further to the chaos, the French began selling muskets to the Ojibwe in the 1680s. Though an Algonquian people, the Ojibwe were eager to ensure they retained their position as the primary middlemen with the French in the beaver trade, a position that was under threat by the French building numerous trading posts along the shores of the Great Lakes. Using their new firearms, they swept south from their ancestral homelands north of the Great Lakes, asserting their dominance over the other Algonquian tribes in the region. Allying themselves with the Sioux and Shawnee, they attacked the Illinois Confederacy. Already decimated by war and disease, the tribes of the confederacy were scattered.
The musket wielding Ojibwe and French attacks on the Iroquois homeland largely ended the Iroquois raids in the Midwest, though the Iroquois retained control of the Ohio Country, which remained largely depopulated. Some members of the tribes who fled west did return to their ancestral homelands in Illinois, Indiana, and Michigan, but many did not, leaving the populations in these areas much sparser than they had once been. For their part, the Ojibwe did little to help the situation, attacking any tribe that did not respect their monopoly on trading with the French. One of their most common targets was the Sioux, many of whom moved further west onto the Plains.
