On this day 250 years ago in Boston, Massachusetts Governor Gage wrote to Governor Josiah Martin of North Carolina that

This Province has some time been, and now is, in the new-fangled Legislature, termed a Provincial Congress, who seem to have taken the Government into their hands. 

Source: https://newenglandhistoricalsociety.com/april-12-1775-gen-thomas-gage-hopes-madness-wears/

On that day in Groton, Massachusetts, the Groton Committee of Inspection published a notice as instructed by the Town Meeting a week earlier. The notice identified the Loyalists in the town who had declined to sign a covenant pledging to honor the Continental Association and read:

In compliance with said vote, we hereby notify the public that said Association paper was offered to the Reverend Samuel Dana, Joseph Sheple, Jonas Cutler, and Joseph Chase, who did refuse to sign the same, and it is expected that all those who have signed said Association will remember their covenant. 

Source: https://www.americanhistorycentral.com/entries/lexington-and-concord-groton-militia/

And on that day in Concord the Massachusetts Provincial Congress passed a resolution that was then posted as a broadside signed with the unmistakeable signature of Congress President John Hancock. The resolution and broadside declared

WHEREAS the Preservation of our Country from Slavery, depends under God, on an effectual Execution of the Continental and Provincial Measures for that Purpose:

RESOLVED, That there be now appointed for each County in this Colony, a Committee consisting of Five Persons, any Three of whom to be a Quorum, whose Business it shall be, to receive from the Committees of Correspondence in their respective Counties, a State of the Conduct of the Towns and Districts, with Respect to their having executed the Continental and Provincial Plans as aforesaid

. . .

And whereas some Towns and Districts in the Colony, may be destitute of so excellent an Institution as Committees of Correspondence :

RESOLVED, That it be, and it hereby is strongly recommended to such Towns and Districts, forthwith to choose them, and to afford them Assistance at all Times, in effectually suppressing the Efforts of the Enemies of America, whenever they shall make them.

These committees were sometimes styled as the “Committee of Safety” and are usually referred to by that name in histories today. The Committee of Safety would serve as the local governing body of each town and county in Massachusetts and the other colonies in the opening years of the Revolutionary War.

Source: Journals of the Provincial Congress of Massachusetts at 139-140 accessed at https://archive.org/details/journalsofeachprma00mass/page/138/mode/2up?view=theater