The Connecticut Compromise, also known as the Great Compromise, was an agreement between large and small states reached during the Philadelphia Convention of 1787 that in part defined the legislative structure and representation that each state would have under the United States Constitution. It proposed a bicameral legislature, resulting in the current United States Senate and House of Representatives.
On May 29, 1787, Edmund Randolph of the Virginia delegation proposed the creation of a bicameral legislature. Membership in the lower house was to be allocated in proportion to state population, and candidates were to be nominated and elected by the people of each state. Membership in the upper house was to be allocated in the same way, but candidates were to be nominated by the state legislatures and elected by the members of the lower house. This proposal was known as the Virginia Plan.
Less populous states like Delaware were afraid that such an arrangement would result in their voices and interests being drowned out by the larger states. Many delegates also felt that the Convention did not have the authority to completely scrap the Articles of Confederation<1>, as the Virginia Plan would have<2>. In response, on June 15, 1787, William Paterson of the New Jersey delegation proposed a legislature consisting of a single house. Each state was to have equal representation in this body, regardless of population. The New Jersey Plan, as it was called, would have left the Articles of Confederation in place, but would have amended them to somewhat increase Congress' powers.<3>
On July 16, 1787, Roger Sherman and Oliver Ellsworth, both of the Connecticut delegation, forged a compromise for a bicameral, or two-part, legislature consisting of a lower and upper house.
In favor of the larger states, membership in the lower house, as in the Virginia Plan, was to be allocated in proportion to state population and candidates were to be nominated and elected by the people of each state. A census of all inhabitants of the United States was to be taken every 10 years. Also all bills for raising taxes, spending or appropriating money, and setting the salaries of Federal officers were to originate in the lower house and be unamendable by the upper house. In exchange, membership in the upper house, however, was more similar to the New Jersey Plan and was to be allocated two seats to each state, regardless of size, with members being chosen by the state legislatures.<4> Members of the Upper House, or Senators, were elected by the State Legislature until the ratification of the Seventeenth Amendment, which called for the direct election of Senators by the people.
http://en.wikipedia.org/wiki/Connecticut_CompromiseThis is like fifth grade social studies info