The 1500s were a time of tremendous change in Europe. Perhaps the two most important changes were the Renaissance and the Reformation.
The Renaissance did not start in 1500. Instead, it had been going on for a long time. However, new ideas were still coming to the fore in the 1500s. One example of this is the fact that Machiavelli wrote The Prince in 1513. This was an example of how ideas about government were changing as some rulers were coming to see power, and not morality or the well-being of the people as the main goal of government.
The Reformation did start in the 1500s. It was one of the most important changes in all of European history. In the Reformation, the Christian church in Western Europe split. Protestants broke away from the Roman Catholic Church. This led to tremendous religious and political conflict as countries took sides and went to war over (at least in part) religion.