Derat's Le domaine des rois éthiopiens (1270-1527): Espace, pouvoir et monachisme is a fascinating study of Solomonic Ethiopia. Derat makes an interesting case for the centrality of Amhara and Sawa as "domains" of the Solomonic rulers in the period 1270-1527. If her interpretation of the royal chronicles, hagiographical literature, monastic chronicles, and other sources (especially Arab Faqih, Francisco Alvares, and other exogenous writings) is correct, then the tradition of Takla Haymanot playing a key role in the rise of the Solomonic dynasty under Yekuno Amlak is an invented one that did not reflect what actually happened in 1270. Instead, she proposes that Dabra Asbo/Libanos (the monastery started by Takla Haymanot in the region of Sawa) invented the tradition of their founder having a central role in the rise of the Solomonic dynasty to increase their prestige. Instead, Dabra Hayq, a monastery started in the 1200s by Iyasus Mo'a, appears to have been more central in the early rise of Yekuno Amlak against the Zagwe dynasty.
She also suggests that these monastic networks were vital for the expansion and extension of the Solomonic dynasty in the two provinces of Amhara and Sawa, mountainous provinces that are defensible and, in the case of the latter, agriculturally rich. So, the Solomonic rulers, especially Zara Ya'eqob and his successors in the 1400s, began to establish and build more monasteries and churches in the provinces (and nearby ones that were recently conquered from Muslims or pagans) and in the process, force prestigious (and formerly autonomous monasteries, like Dabra Asbo) to supply clerics and monks to the religious foundations. In order to grease the wheels, kings like Zara Ya'eqob gave more land as gult or rest to these monasteries, appointed abbots (or tried to do so), used royal monasteries and churches as centers for councils that affected religious policy, and even used others as tombs for kings and pilgrimage centers. She argues that Amhara, and especially Sawa (and later Gojjam) became solidly part of the Solomonic kingdom through these religious networks in which the kings increasingly dominated religious policy and sought to use the "monastic holy man" as a pillar of the kingdom. Unfortunately, Derat's book is somewhat repetitive and her evidence relies on deductions that hope to make sense of fragmentary or contradictory hagiographies and traditions.
But she makes a persuasive case that the image of the monastic holy man changed. Monasteries like Dabra Asbo/Libanos, which once prized the martyr and depicted the Solomonic rulers as corrupt or heretics for having multiple wives, abusing their power, or seeking to change Church doctrine, later shifted to a new image of holiness in which the monastic leadership collaborated with the king to protect Christian society. As one can imagine, this process was part of the strengthening of Solomonic power in Amhara, Sawa and other provinces as the monastic and church network ultimately built or expanded bases of power for the Solomonic rulers. Even in this era of ambulant courts, Solomonic rulers made frequent visits to the religious foundations they sponsored, and those containing tombs for past rulers became centers of pilgrimage and commemoration of the Solomonic rulers. I guess it would have helped to see how this process differed in northern Ethiopia, like in Tigre, where the origins of Ethiopian monasticism could be found. Perhaps a hint can be seen in the way that Yekuno Amlak erected a church in Lasta, the center of the Zagwe dynasty, possibly inserting himself into the tradition of religious pilgrimage and sacred geography espoused by the Zagwe dynasty. Nevertheless, the most interesting figure to emerge out of this history is Zara Ya'eqob, the fascinating emperor who heavily promoted the cult of Mary, reduced the independence of Dabra Asbo, imposed the observation of the Saturday Sabbath, and convened councils on Church doctrine which were destined to support his own views. The guy also wrote a number of homilies and religious treaties and even had two of his wives killed for plotting against him.
I would still like to learn more about the actual process of Christianization of Sawa and other provinces, which is hinted at here or there. We also have some enigmatic references to the Falasha and other non-Christians but it would have been important to see how the Solomonic dynasty asserted itself and its legitimacy in other parts of the empire. Derat suggests some continuity from the Aksumite and Zagwe dynasties in terms of building churches as royal tombs but perhaps opening up to consider Christian rulership in Nubia and the Byzantine Empire would have been fruitful. After all, Ethiopians were still making the pilgrimage to Jerusalem, had contacts with the Coptic Church of Egypt (whose Patriarch also had Nubia in its jurisdiction) and may have sought to establish an Ethiopian "caesaropapism" that may have had parallels in medieval Nubia. Comparisons with Sudanic Africa, as suggested by Donald Crummey, may have been of use, too. After all, one can see some parallels with Islamic kingdoms in the Sudanic belt, despite the obvious differences between Islam and Christianity. The parallels, for instance, with the Sayfawa of Kanem-Borno may offer clues to the allegedly sacred royalty theme. Or, for instance, the support for religious foundations and Islamic holymen found in the Borno mahrams could potentially offer a similar case in which the Sayfawa dynasts used their patronage of Islamic holymen to buttress their authority in disparate regions of their empire.