Among the protagonists of the tenth-century monastic reform movement Abbo occupied an important place. Born around the year 940 in the Orléanais, he was oblate and pupil in Fleury, and also studied in Reims, Paris and Orléans. Abbo developed into a many-sided scholar. In 988 he was elected to the abbacy of Fleury, and from that moment until his death in 1004 he promoted the ideas of the monastic reform movement. The complex relationship of the abbot of Fleury with the diocesan bishop, the king and later, the pope, necessitated Abbo to write several texts in which he dealt, incidentally and among many other things, with political matters. Based on these texts Marco Mostert reconstructs Abbo's political theology, the coherent set of ideas about God, society and the ruler which was the foundation of all his statements on these matters.