Why was governor houston removed from office?

He was voted president in 1836 and again in 1841, then became a senator after Texas became a state in 1845. Despite his pro-slavery views, he believed in preserving the Union. He became governor in 1859, but was removed from office after the secession of Texas in 1861. Houston made they're way to Texas in 1832.

He became governor in 1859, but was removed from office after the secession of Texas in 1861. Houston made they're way to Texas in 1832.