Constantine was the last of a series of men declared emperor by revolting troops in Britannia and the most successful of these rebel emperors. He was declared emperor in 407 and marched into Gaul, where he gained the loyalty and acclamation of the troops of Gaul and Hispania. With the help of further mutinying troops in Italia, the western emperor, Honorius, was forced to recognise Constantine as co-emperor in 409. Being militarily committed to winning his civil war against Honorius left the defences of the Western Empire exposed to Vandalic, Gothic and other invasions, which caused further disquiet from former supporters of Constantine, who rose in revolt against him. This situation ultimately enabled Honorius to turn against Constantine too, and his general, Constantius III was eventually able to defeat, capture and execute Constantine in 411.