No law, varying the compensation for the services of the Senators and Representatives, shall take effect, until an election of Representatives shall have intervened.
James Madison, then a Congressman, was given the task of turning the 200+ demands for a Bill of Rights from the states, into a single, concise list. He drafted 17 Amendments that passed the House. The Senate passed 12 of those.
The original 1st Amendment was defeated and remained dead. The original 2nd Amendment took 203 years to be ratified, as the 27th Amendment. But it is still part of the Bill of Rights as drafted by James Madison.
Though it seems poetic justice that the First Amendment is the "first," that is pure accident. It was originally the "third" amendment.