At the time of European contact, the Illinois economy was largely self-sufficient. In the course of their yearly activities, the Illinois people produced virtually all of the foodstuffs and other material products they needed to maintain their way of life. However, the Illinois also participated in an extensive trading network. In exchange for hides, furs, and human slaves obtained from tribes living to their south and west, the Illinois traded with Great Lakes tribes and French traders for guns and other European goods. As time passed, traders and missionaries began to settle among the Illinois and their formerly self-sufficient economy became increasingly dependent upon their French allies.