When Ralph Waldo Emerson, the Sage of Concord, penned his stirring lines about “embattled farmers” standing by Concord’s North Bridge and firing “the shot heard ’round the world,” he conveniently neglected the exchange of musket fire earlier on the morning of April 19, 1775, when Redcoats and Colonial militia faced off on Lexington’s green.

Perhaps unintentionally, Emerson set in motion a friendly rivalry between the towns over Revolutionary primacy. It comes to a head each year on the third Monday of April, Patriots Day, when reenactors stage the two skirmishes and subsequent running battle, known collectively to schoolchildren everywhere as the Battle of Lexington and Concord. Here’s how the towns stack up on some Revolutionary essentials.

--Patricia Harris and David Lyon/Globe correspondents