The great compromise at the constitutional convention, the one that created our bicameral legislature, was a compromise position of two different plans put forward by the states of and

Virginia 
New Jersey  
On May 29, 1787, Edmund Randolph of Virginia proposed the creation of a two house legislature where each house was populated proportional to its population. This was known as the Virginia Plan and was objected to by the smaller states since they felt that they would be overruled by the larger states. On June 15, 1787, William Paterson proposed a single house legislature with and equal number of representatives from every state. This alternative plan was known as the New Jersey Plan and was objected to by the larger states since they believed that would get more than proportional power to the smaller states. Towards the end of July, 1787, a final compromise of a two house legislature was made with the lower house (House of Representatives) being apportioned by state population and the upper house (Senate) being equally apportioned by each state.