The Constitutional Convention was initially convened by the Congress of the Confederation in 1787 to revise the Articles of Confederation. Under the Articles, the new government had quickly come to a stalemate between the northern states and those in the south. The 55 convention delegates included Benjamin Franklin, Gen. George Washington, James Madison, Gouverneur Morris, James Wilson, Roger Sherman and George Mason.
Rather than revising the Articles, the convention changed course with the recommendation to draft an entirely new document, based on the Virginia Plan. The Virginia Plan was developed by Madison, Morris and Wilson and took a more nationalistic view of the new government than that of the Articles of Confederation. Several compromises were reached by the delegates, including: the Connecticut Compromise (representation by population in the House of Representatives and representation by state in the Senate); the veto power by the President which could be overridden by a two-thirds vote of Congress; and the Three-Fifths Compromise over slavery.
The new document was endorsed by 39 of the delegates on September 17, 1787, and sent to the Congress of the Confederation, which then submitted it to the states for ratification. When 11 states had ratified it, the Congress called for the states to hold elections for offices under the new Constitution. It then dissolved itself on March 4, 1789, the first meeting day of the new Congress. Following the elections, George Washington was inaugurated as the first President on April 30, 1789. The first Congress quickly passed legislation to set the new government into operation, including the Judiciary Act of 1789.
A notable objection to the Constitution was that it lacked a bill of rights for citizens. Madison drafted the first ten Amendments to the Constitution to answer that objection. The first of these was ratified in 1791.
The Thirteenth Amendment finally abolished slavery in 1865, with the Fourteenth Amendment in 1868 granting citizenship to former slaves. The Fifteenth Amendment in 1870 prohibited the use of race, color or former servitude to determine who could vote. It wasn’t until 1920, however, that women were given the right to vote under the Constitution with the ratification of the Nineteenth Amendment.
The Constituion, including all ratified and unratified Amendments, is available as a House Document.
Read more about the Constitutional history of the United States:
Edgar J. McManus & Tara Helfman, Liberty and Union: A Constitutional History of the United States (2014).
Howard Gillman & Mark A. Graber, American Constitutionalism (2017).
Update (Sept. 16, 2019):
The Library of Congress has just released its online Constitution Annotated, prepared by the American Law Division of the Congressional Research Service.