Which ruled constantinople for 50 years during the early 1200s

The one that ruled Constantinople for 50 years during the early 1200s were: the Western Christians
The empire that reign over the Constantinople during that time was a Muslim empire. So the Latin Churches gathered a group of army and called themselves the Crusaders to take back the Constantinople. They managed to win and reign that region for 50 years.

They were eliminating problems caused by industrialization, urbanization, immigration, and corruption in government