At issue was who, the pope or monarchs, had the authority to appoint (invest) local church officials such as bishops of cities and abbots of monasteries. The conflict ended in 1122, when Emperor Henry V and Pope Calixtus II agreed on the Concordat of Worms. It differentiated between the royal and spiritual powers and gave the emperors a limited role in selecting bishops.
The first two US political parties were technically the Federalists and the Anti-Federalists, who were later known as the Democratic and Republican parties.
Currently, the United States has two major political parties, the Democratic party and the Republican party. There are also various third parties, but their political clout is generally considered marginal at best. Roughly speaking, political parties serve the same purpose in the political world as denominations or sects serve in the religious world. If an individual were the only person alive on an island, his or her word would be considered law.