He elevated his son , Tetricus II , to caesar in 273 to increase his support .
In late 271 , Tetricus moved the capital of the Gallic Empire from Cologne to Trier .
Tetricus elevated Tetricus ' son Tetricus   II , to caesar in 273 to increase his support .
In late 271 , Tetricus moved the capital of the Gallic Empire from Cologne to Trier .