Complex sentence: When the company's term of enlistment expired, Bosbyshell rejoined Union forces as a second lieutenant in Company G, 48th Pennsylvania Volunteers, to serve a three-year term from October 1,1861.
Split into simpler sentences: When the company's term of enlistment expired, Bosbyshell rejoined Union forces as a second lieutenant in Company G, 48th Pennsylvania Volunteers. He joined the company for a three-year term from October 1,1861.