What was the purpose of the great compromise?

It was a compromise of both the federalists, anti federalists, and the Virginia plan, New Jersey plan, when the constitution was being drafted

It resulted in two houses of Congress the Senate (equal representation, 2 Senators every state) and House of Representatives (representation according to population)

To settle the method of representation in the legislative branch.

Northern states wanted representation based on the population, which would mean all larger states whom at the time had the most people living within would dominate Congress. Under the Compromise, all states were represented equally within the Senate.