Streams of Gold, Rivers of Blood

Just read Anthony Kaldellis's Streams of Gold, Rivers of Blood. It's about the rise and fall of the renewed Byzantine Empire under the Macedonian dynasty expansionist phase and the rapid near collapse in the late 11th century. He really pushes back against the idea that Constantine Monomachos was an incompetent ruler. He also reemphasizes the weakness of the "feudalization" theory for understanding how the Empire declined. We also lack evidence of any extensive "fiscalization" of thematic lands that would have made the empire more dependent on professional soldiers instead of thematic ones, although the professional soldiers would have been more mobile and effective than the thematic soldiery. He also argues that the First Crusade, until the Latins took Antioch, was largely following the imperial agenda of Alexios Komnenos who supplied them and gave them direction after forcing/encouraging them to promise to return old Byzantine territories to  the Empire. 

While we are not entirely sure about that part of the book, the main argument he's making is that what caused the rapid decline of the empire (which had expanded in the east through the reconquest of parts of southeastern Anatolia, Antioch, northern Mesopotamia, Crete, Armenia, parts of the Caucasus, and Bulgaria and parts of the Balkans in the 900s and early 1000s), was the return to multipolarity at a bad time (war on three fronts with Seljuk Turks, Pechenegs, and Normans). The Empire had been so centralized by Basil II during his long reign and then returned to business as usual as the Macedonian dynasty entered several problematic successions as Basil II never had children and his brother only had 2 daughters. One daughter married different men and arrangements were made to preserve the line but Byzantium returned to business as usual (i.e., lack of established principle of succession and return to competition whenever the imperial center was or looked weak) led to succession conflicts and contested imperial rule.

Kaldellis is a funny academic. In the Introduction, he claims to harbor no affection for the Byzantine imperial project, but he repeatedly laments the treacherous Normans and others who seized and attacked Byzantium. We are a little disappointed he largely omitted the Norman-Byzantine wars of the 1080s to skip ahead to the First Crusade, but I guess his account really pushes back against Michael Psellos's Chronographia and Skylitzes to some extent. The Byzantine state was devaluing currency in the 1000s and appears to have become excessive with the giving of titles and gifts at each new succession to buy loyalty (which became necessary with emperors who had less legitimacy felt insecure), which sort ofsupports what Psellos wrote in the 11th century about how the emperors after Basil II began wasting a lot of funds of the imperial treasury. But since we lack enough hard data or facts about the nature of the economy, Kaldellis instead doesn't see any defunding of the military until after Constantine Monomachos, who is presented as one of the last decent emperors before Manzikert.

The situation in the 1070s-1080s was a disaster (one of the Normans hired by the Byzantines also made things worse by plundering and demanding protection money and then rebelling against the Byzantines while the Seljuks were raiding and seizing more lands). But when the Komnenos take back large sections of Asia Minor, was there a large enough Christian population resettling in those areas? I assume the Armenians in Cilicia and whatnot remained to a large extent and the area that later became Trebizond south of the Black Sea held out against the Ottomans until the 1400s but in terms of demographics, it does appear that so much of Asia Minor was permanently lost. Perhaps, with better luck, the Byzantines may have been able to hold Asia Minor if they did not have to address threats and attacks from other fronts.