The tavern is sometimes called the "Headquarters of the Revolution", though I imagine when it is, they pronounce it "Headquartersh of the Revolushun", because overthrowing the government in a pub is thirsty work.
It was a popular place for people like Paul Revere and Samuel Adams to sit with their friends and plot.
Up until 1754, the tavern was owned by William Douglass. When he died, his property was left to his daughter, Catherine Kerr, and his nephew, Cornelius Douglass. They divided their inheritance equally - and it seems, got along famously.
The Freemasons bought the tavern in 1766 and renamed it "The Freemasons Arms", which didn't actually stick because the sign above the door was still a Green Dragon. (Freemasons: the secret society everyone knows about. "Let's get a pub where we can meet in complete secret and no one will ever know!" - "Brilliant! What shall we call it?" - "How about the Freemasons Arms?")
Legend has it that Paul Revere's ride was planned here, but that's unlikely. By 1774 Revere had been warned that the British were listening in on his meetings and had therefore stopped making Super Secret Plans in public where anyone could hear them.
Someone tell the Masons. You know where to find them.