I believe your answer is the Aztecs.
In Early Philadelphia a lot happened like there were houses that needed to be built also colonies were hard to keep up with.
During the Civil War the northerners fought because they were against slavery, the southerners fought because the slaves did the work for them.
It was the "B. Plebeians" who made up the majority of the roman population and became citizen-soldiers during the time of war, since these were the "common" people as opposed to the elite.
For the Louisiana purchase question, it more than doubled the size of the united states. As for the second question I believe the answer would be "Thomas Jefferson was eager to explore the west to ensure the survival and prosperity of the United States"