William Ellery was the son of a successful merchant and politician in Newport, Rhode Island. Like his father, Ellery attended Harvard, graduating in 1747 and later engaging in business and practising law in Newport in 1770. Ellery was an influential member in the Continental Congress in 1776. As a signer, his signature on the Declaration of Independence was second in size to John Hancock’s famous signature. He went on to be a signer the Articles of Confederation. In 1785 he was an active supporter of Rufus King in his effort to abolish slavery throughout the country. King was a congressman who added provisions to the 1785 Northwest Ordinance which barred the extension of slavery into the Northwest Territory.

Source:
https://freemasoninformation.com/masonic-education/famous/united-states-masonic-founding-fathers/