In the 1850s they defended slavery in the United States, and promoted its expansion into the West against northern Free Soil opposition.
This is straight from the internet, "<span>The </span>causes<span> of the </span>fall of the Soviet Union<span> were many and included ethnic conflict, a lack of support for the idea of communism and economic troubles </span>caused<span> by a focus on arms. Despite reform efforts by Mikhail Gorbachev, the then leader of the</span>Soviet Union<span>, the country was never able to reorganize and rebuild."</span>
The Classical Era set the scene. It brought us the major civilizations, religions, and trade routes. But, what happens when all of the major world powers collapse? This is the Post-Classical era. The major world powers come from places you might not expect. There are some powers that are similar to the ones before and the ones after (Byzantine, China). But, the major players in the Post-Classical era come from totally backwards places. One sprouts out of a cave in the Arabian desert. The other comes from the base of a mountain on the steppes in Central Asia. I call this era, Muslims & Mongols. That's not everything, but it just about sums up the basics. (Of course, Trade, Migrations, Religion, and Labor are important...) The Post Classical Era is the FIRST era that represents 20% of the test. From here on out, these eras are worth more than the first two.