Old English ofercuman "to reach, overtake, move or pass over," also "to conquer, prevail over, defeat in combat" (the Devil, evil spirits, sin, temptation, etc.), from ofer (see over) + cuman "to come" (see come (v.)). A common Germanic compound (Middle Dutch overkomen, Old High German ubarqueman, German überkommen).
In reference to mental or chemical force, "to overwhelm, render helpless," it is in late Old English. Meaning "to surmount (a difficulty or obstacle); succeed, be successful" is from c. 1200. The Civil Rights anthem "We Shall Overcome" was put together c. 1950s from the lyrics of Charles Tindley's spiritual "I'll Overcome Some Day" (1901) and the melody from the pre-Civil War spiritual "No More Auction Block for Me." Related: Overcame; overcoming.