The Virginia Plan emerged during the Constitutional Convention in 1787. It was a proposal presented by the delegates from Virginia and drafted by James Madison and it promoted the establishment of a bicameral legislative branch of power. Power in the US was already divided between three independent branches: legislative, executive and judiciary and each was granted with powers to supervise the other two.
The Virginia Plan proposed a system of representation based on population weights and, like this, apportionment appeared in US politics, which defines the manner in which seats are distributed in a legislative body, among administrative divisions entitled to representation, in this case, these divisions are the different states that conform the US.