Conversation so far:
What was Lew Wallace's early life like as a child?
In 1832 the Lew Wallace family moved to Covington, Indiana, where Lew's mother died from tuberculosis on July 14, 1834.
What happened to Lew Wallace after his mother died?
At the age of nine, Lew Wallace joined his older brother in Crawfordsville, Indiana, where he briefly attended the preparatory school division of Wabash College.
Did Lew Wallace finish public school?
In 1840, when Lew Wallace was thirteen, his father sent him to a private academy at Centerville, Indiana, where his teacher encouraged Lew's natural affinity for writing.
What did Lew Wallace do to earn more wages?
Sixteen-year-old Lew Wallace went out to earn his own wages in 1842, after his father refused to pay for more schooling.

Question: When did he join the military?
Self-contained rewrite: When did Lew Wallace join the military?