Complex sentence: Wen refused both and suffered for 4 years in a military prison before his execution in which time he wrote many famous historical poems such as the "Song of Righteousness" (Zhengqige), and "Passing Lingdingyang".
Split into simpler sentences: Wen refused both and suffered for 4 years in a military prison before his execution. During this time he wrote many famous historical poems such as the "Song of Righteousness" (Zhengqige), and "Passing Lingdingyang".