Simplify the following text for a Grade 6 native English-speaking person.
Original: Instead , he had to content himself with subduing the fortresses that still held out against him , and the only other notable event of 216 BC was the defection of certain Italian territories , including Capua , the second largest city of Italy , which Hannibal made his new base .
Simplified: Hannibal made his new base in Capua , the second largest city of Italy .