yagbe'u seyon served as co-ruler with his father yekuno amlak for the last few years of his reign, which eased his succession. a memorandum in the four gospels of iyasus mo'a of a gift of vestments and utensils to istifanos monastery in lake hayq states these gifts were in the name of both yekuno amlak and his son yagbe'u seyon. he sought to improve the relations of his kingdom with his muslim neighbors; however, like his father, he was unsuccessful in convincing the powers in egypt to ordain an "abuna" or metropolitan for the ethiopian orthodox church. a letter from him to the sultan of egypt, dated ramadhan a.h. 689 (towards the end of ad 1289) is mentioned in etienne marc quatremère's "mémoires géographiques et historiques sur l'égypte… sur quelques contrées voisines" (paris, 1811), where he protests the sultan's treatment of his christian subjects, stating that he was a protector of his own muslim subjects.