The idea behind advantageous intermarriages within the Choctaw nation probably didn't begin with the European influence, however, there is little documentation to state this as a fact. What is evident however, from the earliest period of documentation available, is that this practice not only existed, it flourished in the late 18th and early 19th century.
Several excellent historical publications over the last decade have examined earlier Choctaw history in the 18th century. Often the information about the politics of the Choctaw Civil war of the 1750's is hard to decipher. The period after the civil war until the 1780's has received more coverage, but the bulk of information really starts with 1780 and moves forward.
Starting with the Spanish period in 1780 we see letters and documents that give clues to the leadership and politics within the Choctaw nation. A Spanish treaty of 1784 that lists Mingos and leaders from the entire nation, however, shows the complexity of interpreting this information. This is because often one name will be present in more than one place. While we have the availability of some early documentation of towns, most notably Bernard Roman's map, that does little to illuminate answers.
An explanation of the medal system may be in order before I continue. The Spanish, like their predecessors issued medals to various individuals among the Natives that they traded and negotiated with. A large medal leader was a major influential individual chosen by the Spanish to represent the group. A minor medal leader was a leader of a town or an influential individual who lacked what the Spanish perceived as the political clout of the large medal leader.
Among the various Mingos and leaders, holding a medal was a covetous position. Although the Europeans considered them uncivilized, the Choctaws saw advantages in the perception of esteem and status that the medals provided. They also coveted the trade goods that they received in exchange.
The most prominent medal holder for the Western district, known as Okla Fayala, during the last two decades was Franchiamastubbee and his spokesperson Tobacca. It is presumption among historians that Tobacca was likely connected to Franchiamastubbee by marriage, and that Franchiamastubbee's successor, Apuckshunnubbee was most likely a nephew. The question still remains if Peyahuma (most correctly Opia Humma, a war prophet) was the father of Apuckshunnubbee and a brother in law of Franchiamastubbee.
In the eastern and southern districts it is not as clear. There are two Mingo Poos Coos, one who appears to be closer to the boarder of the Eastern district and the Southern district, and one who was in clearly in the Eastern district. The later prominence of Mingo Homomastubbee in the early 19th century stems from an unclear path. A lot of power in the earlier treaties seems to stem from the Chickashaway, but evidence suggests that Homomastubbee resided further northeast.
The Southern districts that included the Six Towns and the Kunsha also appears to have included Chickasahaway at times and not at others, increasing the confusion. The independent influence of the different groups within the Southern District is evident in negotiations in treaties up to the treaty of 1830. Although we often see the Six Town representatives separately, the prominent leadership of the Southern district appears to come from a Kunsha in most cases. This may suggest that at least one of the Poos Coos was of Kunsha and not Chickashaway influence.
Two separate pockets of influence also appear to reside in those of Shakihuma heritage with one group residing between the Choctaw and Chickasaw in the Yalobusha area, and the other to the east in the area separating the Choctaw and Chickasaw in the Eastern District. Two distinct family groups from these pockets show prominence in later treaties of both the Choctaw and Chickasaw.
The influx of traders in the Choctaw nation beginning with the documentation found in the 1770's and through tracing their descendants shows the presence of relationships that were advantageous to both the trader and Choctaws formed through the marriages and relationships the traders develop with the female relatives of the leaders, most of whom are large medal holders.
This use of marriages to cement alliances isn't a new concept. We see it throughout European history, and among the Choctaw, Chickasaw and Creek there also existed this concept. Documented marriages between the influential Chickasaw Colbert family and the Lower Creek families exists. Though with the onset of war between the tribes, it wasn't unheard of for the wives to be killed if the two nations were at war among the Creeks.
Just as history records the marriages of nobility in Europe to ensure peace or trade, the Natives of the South East practiced the same concept. While the idea of nobility as it applies to Natives is rejected outright, most historians agree that there was an elite class within these nations. It is my belief that the perpetuation of the elite status both within the full blood Choctaws and the mixed blood progeny of the traders is a direct influence to the events and leadership within the Choctaw nation after the treaty of 1830 until the United States Civil War.