It was a muggy June day in 1882 in New York City and Manhattan College was playing the semi-pro Metropolitans, when Brother Jasper Brennan, the team’s first manager, noticed his students getting restless during the seventh inning, according to Mental Floss. The students were expected to sit quietly in their seats during the game. Brennan called time out and told the students to get up and stretch.
Brennan was an Irish immigrant who started at the college in 1861 and would become the school’s first athletic director, per Manhattan College. He introduced a number of new activities to the school, including the band, glee club, and baseball. Brennan’s order for the students to stretch during the inning became a regular event, which soon caught on with the New York Giants who sometimes played the college, according to the Associated Press. “I guess that version comes as close as any other,” baseball historian Cliff Kachline told the Associated Press in 1982. “But there have been so many origins in baseball that haven’t been nailed down.” There’s an even earlier account of the seventh-inning stretch.