Shortly before his death in 855, the Emperor Lothar I, Charlemagne's grandson, wrote to Hrabanus Maurus, monk, reknowned theologian and at this date archbishop of Mainz. He commissioned a liturgical compendium for use on his travels, containing the readings for mass all year round, each accompanied by its own explanatory homily (expositio et omiliaticus sermo). The homilies were to be read aloud to the emperor during meals, to sustain his homo interior with the infinite riches of spiritual food while he sat down at the imperial table. Apparently earlier efforts to gather suitable homilies for the annual liturgical cycle had failed in the face of an overwhelming and impenetrable amount of patristic commentary. Lothar's requirements were specific. Not only did the emperor need homilies for ordinary Sundays and feast days, but also for a host of special masses: on fast days or rogations, against invading armies, famine and poverty, against winter floods, barren earth and failing harvest; for a multitude of saints' days, for Ember Days, for the commemoration of the dead and for ceremonies of consecration – and there would be other masses of which Hrabanus could easily think if he put his mind to it. Furthermore, Jacob's blessings for his sons should be added, along with the benedictions Moses pronounced over the people of Israel on the eve of his death, as well as sermons for All Souls and the Invention of the Holy Cross.