<P> Once the immediate task of winning the American Revolutionary War had passed, the states began to look to their own interests, and disputes arose . These included a dispute between Maryland and Virginia over the Potomac River and opposition to Rhode Island's imposing taxes on all traffic passing through it on the post road that linked all the states . James Madison suggested that state governments should appoint commissioners "to take into consideration the trade of the United States; to examine the relative situation and trade of said states; to consider how far a uniform system in their commercial regulations may be necessary to their common interests and permanent harmony". </P> <P> Another impetus for the convention was Shays' Rebellion . A political conflict between Boston merchants and rural farmers over issues such as property seizures for tax debts had broken out into an open rebellion . This rebellion was led by a former Revolutionary War captain, Daniel Shays, himself a small farmer with tax debts, who had never received payment for his service in the Continental Army . The rebellion took months for Massachusetts to put down completely, and some desired a federal army that would be able to put down such insurrections . </P> <P> In September 1786, at the Annapolis Convention, delegates from five states called for a Constitutional Convention in order to discuss possible improvements to the Articles of Confederation . The Constitutional Convention took place in Philadelphia on May 14, 1787 . Rhode Island, fearing that the Convention would work to its disadvantage, boycotted the Convention and, when the Constitution was put to the states, initially refused to ratify it . </P> <P> Due to the difficulty of travel in the late 18th century, very few of the selected delegates were present on the designated day of May 14, 1787, and it was not until May 25 that a quorum of seven states was secured . (New Hampshire delegates would not join the Convention until more than halfway through the proceedings, on July 23 .) James Madison arrived first, and soon most of the Virginia delegation arrived . While waiting for the other delegates, the Virginia delegation produced the Virginia Plan, which was designed and written by James Madison . On May 25, the delegations convened in the Pennsylvania State House . </P>

Who called for the constitutional convention to be held