early 13c., from Old French menestrel "entertainer, poet, musician; servant, workman; good-for-nothing, rogue," from Medieval Latin ministralis "servant, jester, singer," from Late Latin ministerialem (nominative ministerialis) "imperial household officer, one having an official duty," from ministerialis (adj.) "ministerial," from Latin ministerium (see ministry). The connecting notion is via the jester, etc., as a court position.
Specific sense of "musician" developed in Old French, but in English until 16c. the word was used of anyone (singers, storytellers, jugglers, buffoons) whose profession was to entertain patrons. Only in 18c. was the word limited, in a historical sense, to "medieval singer of heroic or lyric poetry who accompanied himself on a stringed instrument." Reference to blackface music acts in U.S. is from 1843.