Question: how old was abner doubleday when he invented baseball

title: Abner Doubleday
text: At the start of the Battle of Gettysburg , July 1 , 1863 , Doubleday 's division was the second infantry division on the field to reinforce the cavalry division of Brigadier General John Buford . When his corps commander , Major General John F. Reynolds , was killed very early in the fighting , Doubleday found himself in command of the corps at 10 : 50 am . His men fought well in the morning , putting up a stout resistance , but as overwhelming Confederate forces massed against them , their line eventually broke and they retreated back through the town of Gettysburg to the relative safety of Cemetery Hill south of town . It was Doubleday 's finest performance during the war , five hours leading 9,500 men against ten Confederate brigades that numbered more than 16,000 . Seven of those brigades sustained casualties that ranged from 35 to 50 percent , indicating the ferocity of the Union defense . On Cemetery Hill , however , the I Corps could muster only a third of its men as effective for duty , and the corps was essentially destroyed as a combat force for the rest of the battle ; it would be decommissioned in March 1864 , its surviving units consolidated into other corps .