Committees of correspondence
The committees of correspondence were a collection of American political organizations that sought to coordinate opposition to the British Parliament and, later, support for American independence during the American Revolution. The brainchild of Samuel Adams, a Patriot from Boston, the committees sought to establish, through the writing of letters, an underground network of communication among Patriot leaders in the Thirteen Colonies.
Source: Wikipedia — Committees of correspondence (CC BY-SA 4.0)