All told, 55 delegates participated in some way in the Constitutional Convention, but some left early and others (including Elbridge Gerry and George Mason) refused to sign it. When the Constitution was fully written, only 39 delegates signed it on September 17, 1787, which is honored annually as "Constitution Day." | All told, 55 delegates participated in some way in the Constitutional Convention, but some left early and others (including Elbridge Gerry and George Mason) refused to sign it. When the Constitution was fully written, only 39 delegates signed it on September 17, 1787, which is honored annually as "Constitution Day." |