There was a time, early in the 19th century, when baseball was a gentlemanly game played by the upper class. Things changed when second-generation Irish immigrants took an interest. “The Irish had a huge influence on the development of early American baseball,” says Brian Sheehy, history teacher and sports scholar. “Without the Irish, baseball may not have become the game it is today.” Speed and a certain competitive rowdiness — think cutthroat — usurped polite gentility. Add to that a natural athletic prowess that upped the ante and made baseball the all-American sport it is today. All are invited to a summertime presentation at The House of the Seven Gables on Tuesday, Aug. 13, 6:30 to 8 p.m. Brian Sheehy is head of the history department at North Andover High School and national lecturer on 19th century baseball. His presentation, “The Emerald Diamond: The Influence and Role of the Irish on Baseball’s Development,” is a fascinating look at the development of America’s favorite pastime. His talk, the fifth in this year’s Seven Lectures at Seven Gables series, also delves into the important role sports play in the influence and acceptance of immigrants in our society. The House of the Seven Gables is located at 115 Derby St., Salem. Some parking is available onsite. Admission is $10 and registration is always advised. Call 978-306-7003, email firstname.lastname@example.org or register here. “Sports are a vehicle for transcending any kind of boundaries,” Sheehy says. “In society we are always drawing boundaries. Sports break them down in many cases. If you are successful in hitting a baseball, a lot of the time your ethnic background is ignored. In other words, you are American if you can play the game.” Sheehy is president of Essex Base Ball Organization and he has played 19th century baseball for nearly two decades. For more information about his organization and the game of early baseball, visit essexbaseball.wordpress.com.