organizations formed in the American colonies in the summer of 1765 to oppose the Stamp Act. They took their name from a speech given in the British Parliament by Isaac Barré (February 1765), in which he referred to the colonials who had opposed unjust British measures as the “sons of liberty.” They rallied support for colonial resistance through the use of petitions, assemblies, and propaganda, and they sometimes resorted to violence against officials of the mother country. Instrumental in preventing the enforcement of the Stamp Act, they remained an active pre-Revolutionary force against the crown.