Then Province of Maryland had been a British / English colony since 1632, when Sir George Calvert, first Baron of Baltimore and Lord Baltimore (1579-1632), received a charter and grant from King Charles I of England and first created a haven for English Roman Catholics in the New World, with his son, Cecilius Calvert (1605-1675), the second Lord Baltimore equipping and sending over the first colonists to the Chesapeake Bay region in March 1634. The first signs of rebellion against the mother country occurred in 1765, when the tax collector Zachariah Hood was injured while landing at the second provincial capital of Annapolis docks, arguably the first violent resistance to British taxation in the colonies. After a decade of bitter argument and internal discord, Maryland declared itself a sovereign state in 1776. The province was one of the Thirteen Colonies of British America to declare independence from Great Britain and joined the others in signing a collective Declaration of Independence that summer in the Second Continental Congress in nearby Philadelphia. Samuel Chase, William Paca, Thomas Stone, and Charles Carroll of Carrollton signed on Maryland's behalf.
Although no major Battles of the American Revolutionary War (1775-1783) occurred in Maryland itself, (although the British Royal Navy fleet passed through and up the Bay to land troops at the "Head of Elk"), to attack the colonies' capital city, this did not prevent the state's soldiers from distinguishing themselves through their service. General George Washington counted the "Maryland Line" regiment who fought in the Continental Army especially the famed "Maryland 400" during the Battle of Brooklyn in August 1776, outside New York Town as among his finest soldiers, and Maryland is still known as "The Old Line State" today.
During the war itself, Baltimore Town served as the temporary capital of the colonies when the Second Continental Congress met there during December 1776 to February 1777, after Philadelphia had been threatened with occupation by the British "Redcoats". Towards the end of the struggle, from November 26, 1783, to June 3, 1784, the state's capital Annapolis, briefly served as the capital of the fledgling confederation government (1781-1789) of the United States of America, and it was in the Old Senate Chamber of the Maryland State House on State Circle in Annapolis that General George Washington famously resigned his commission as commander in chief of the Continental Army on December 23, 1783. It was also there that the Treaty of Paris, which ended the Revolutionary War, was ratified by the Confederation Congress on January 14, 1784.
Like other states, Maryland was bitterly divided by the war; many Loyalists refused to join the Revolution, and saw their lands and estates confiscated as a consequence. The Barons Baltimore, who before the war had exercised almost feudal power in Maryland, were among the biggest losers. Almost the entire political elite of the province was overthrown, replaced by an entirely new political class, loyal to a new national political structure.