 Not only did it hold back the Saracens, but some of Byzantium's lost lands were recaptured.The thematic armies also vanquished many other foes including the Bulgars, Avars, Slavs and Varangians, some of whom eventually ended up in the service of Constantinople as allies or mercenaries.In addition to the themes, there was also the central imperial army stationed in and near Constantinople called the Tagmata.