Complex sentence: Hangzhou was declared the new capital of the Song Dynasty in 1132, and would remain the capital of the Southern Song for the next 150 years, despite the Song court's treatment of the city as just a temporary capital.
Split into simpler sentences: Hangzhou was declared the new capital of the Song Dynasty in 1132. Hangzhou would remain the capital of the Southern Song for the next 150 years, despite the Song court's treatment of the city as just a temporary capital.