Hi. You did not present the cover of the magazine to which this question refers, which makes it impossible for this question to be answered. However, I will try to help you as best I can.
A historical circumstance refers to a condition for a historical event to happen, that is, this circumstance is referring to a historical event that caused another historical event of greater impact and proportion. Therefore, to answer your question, you must analyze the cover of your magazine and identify which circumstance, which historical event, which provoked another historical event, this cover addresses.
All are tied up to a revolution that provided the lower class people new grounds to stand on. In the mist of the revolutions a sense of national pride is common place.
It might be either Paleo or plains indians.
The two participants were Abraham Lincoln and Senator Stephen Douglas
