A perfect harmony between the Senate and the House of Representatives which is the foundation of the US Congress is a result of the Great Compromise of 1787. Much prior to this, there was an extreme resistance involving the concept and representation of these two.
The resistance was based on two principles. First, considering the population as the decisive factor for representation; how will states with lesser population be represented, and second, if the size of the state was considered, then the larger states would be represented in more numbers. The tussle between the larger and smaller states continued for years, till a compromise was arrived at in 1787. This compromise was remarked as a crucial event in the history of the United States.
Great Compromise is often regarded as Sherman's Compromise since Roger Sherman along with Oliver Ellsworth had pioneered in putting forth this unusual agreement. It began in the May 1787 when Sherman had picked certain inferences from the Virginia and the New Jersey plans. According to the Virginia plan, the representation would depend on the population of the state. However, the New Jersey plan stated that allocation of representatives will have no influence on the size and the population of the state which resulted in allocation of two legislatures from each state. Until the 17th Amendment, initially representations from the upper house were chosen and elected by the State legislature. The purpose of the 17th Amendment was to elect senators directly. The Great Compromise, therefore, is considered to be lifted from these two plans and this gave birth to the bicameral legislature. On 16th July 1787 the agreement was finally passed after a huge round of debate and discussion.