"That's where it all started, right where you live. You know why they call your school the Harrington school? It's named after one of the men who died..."

A small Lexingtonian heard this history lesson from his father yesterday on the 213th anniversary of the day when a New England militia first fired on British troops. It was a quarter past six in the morning and a clammy 45 degrees Fahrenheit outside, but several thousand people *** Lexington's Battle Green to watch a reenactment of that confrontation.

Some tempers cracked under the strain of the early hour, letting out signs of patriotic fervor. "That's an absurd rule. Isn't that what the Revolution was about?" said one man, angered by the demands of a security officer in 18th-century uniform that he stay behind the ropes.

But for the most part, the spectators bore the cold and the crowding cheerfully. Many regulars had anticipated the need to see past the fellow patriots who surrounded the Green six deep. The rear of the crowd was a solid row of stepladders, chairs and kitchen stools.

Kevin Doyle, a 12-year veteran of the ceremony, welcomed the crowd over an anachronistic loudspeaker, describing--for those who did not know it by heart--the incident where, as he put it, "was born the idea of revolution and liberty." Although Doyle gets up at 4 a.m. each Patriots' Day, he said he has never overslept.

Doyle described the forewarned colonists' resistance to Major Pitcairn's British Regulars ("General Parker will steady his men and exhort them to courage..."), and General Thaddeus Parker's famous order, "Don't fire until fired upon, but if they will have war, let it begin here."

Real flintlocks--and camera shutters--fired, setting up clouds of smoke. Some on each side looked rather convincingly wounded, and wives in frilly caps and wool cloaks ran out to nurse their men.

Following the battle, Doyle announced that the disappearing Redcoats would proceed to Boston, suffering heavy losses from rebel guerilla troops on the way. As he announced the day's losses--Colonials 49, Redcoats 73, the crowd clapped and cheered for the home team.

Marianne Higgins of Lexington said she has brought her children to the reenactment every year since 1975. Her 9-year-old youngest son was engaged in selecting a costumed "Minuteman" with whom to have his picture taken, in an annual family tradition. "Anyone with a gun," he stipulated.

As the annual Patriots' Day parade formed afterwards, nobody objected to the participation of the Upper Darby Marching Royals.