Military reforms after the battle of Manzikert?

Question

After the battle of Manzikert and during Alexius's reign was there any attempt towards military reform to go back to the theme peasant-soldier system instead of mercenaries?

In John Julius Norwich's Byzantine Empire he suggests that one of the reasons the Byzantines lost the battle of Manzikert was the Emperor Ducas's weakening the military by using mercenaries which were unreliable prior to Emperor Romanos Diogenes and a relative of Ducas's betrayal in battle along with splitting the army and marching too late into the day.

Did Emperor Alexius do anything to go back to the theme peasant-soldier system instead of mercenaries?

The reason usually given is that because the Byzantines lost most of Asia minor they lost most of the peasant-soldier population but surely between the rest of the remaining Balkans and a little bit of Italy until he lost it to the Normans there should have still been a large manpower available for a peasant-soldier theme system to work.

Or was he also scared to go back to a powerful military class that could oust him at anytime? If so he clearly put himself before the interests of the Empire and as such maybe was not such a good emperor. But this would be strange given that his uncle emperor Isaac tried to reform the military back to prominence.

It does seem strange given that Roman/Byzantine armies had been smashed to pieces before and even harder that they should have not recovered.

Answer 1

Emperor Alexios was the first (out of four) members of the Komnenos Dynasty, who instituted the Komnenos reforms.

Because it was (initially) a "faction" of the Byzantine Empire, rather than representatives of the Empire itself, they went back to using their own "native" troops of peasant soldiers, rather than mercenaries. The defeat at Manzikert had made this possible by decimating the former Byzantine military class (which favored using mercenaries), plus the loss of the mercenaries themselves.

Using troops from their original bases in the Balkans, first Alexios then his son John had to first defeat European invaders of the Balkans, such as the Pechenegs and the Hungarians. These successes built up the strength of the Komnenon army, which was then able to wrest much of the Black Sea coast and the western coast of modern "Turkey" from the Seljuks.

It was a see-saw fight for about a century, but the Komnenos were much better defenders of the Byzantine empire than their predecessors. When they finally lost a battle against the Turks at Myriokephalon, in 1176, it was a far less decisive defeat than that at Manzikert a century earlier.