Complex sentence: Syrgiannes was freed, and was able to restore himself to Andronikos'favour, to the extent that in late 1329 he was entrusted with the important governorship of Thessalonica, the Empire's second-largest city, and of western Macedonia and Albania.
Split into simpler sentences: Syrgiannes was freed, and was able to restore himself to Andronikos'favour. In late 1329, he was given the important governorship of Thessalonica, the Empire's second-largest city, and of western Macedonia and Albania.