Compare the rules of the catholic church in the 16th century with that of today. How has the church changed and how has it remaind the same?

In the 16th century, the Catholic Church had a lot of practices going on that clerics within the church were opposed to. That is why Martin Luther, who was a priest, nailed his 95 theses to the door of the cathedral in Wittenberg. If you do some research, you can find the 95 theses online and see what Martin Luther opposed - the sale of indulgences, for example, confessing to a priest instead of directly to God, etc. However, it depends on what you mean by "rules" - because the church had rules that were not necessarily being followed. Sinful men were perverting the rules and the church was accused of corruption. However, the sacrements and rules of the church remained the same and some of them are still the same.

Something that had a huge influence on changes in the modern church was a council called Vatican II. If you research this, you will see how the modern church is different today even more. For example, it used to not be OK to be cremated in the Catholic Church, but Vatican II changed that. The modern church is not required to have the mass in Latin. In many modern churches now, the priest faces the people, not the altar -- things like that. These are "practices" of the church, that is why I ask about what you mean by rules.

As far as sacrements and tenets of the church, those have remained pretty constant. There are still 7 sacrements and rules regarding them, abortion is still not OK, priests still cannot marry, but there have been changes made to confession and communion. However, Catholics still believe in many of the same things.