Leo van Kessel was a Holy Ghost father worked as a seminary professor in Bagamoyo. He is an author of several religious books published from 1959 onwards, and he was interested in Swahili poetry as well. He edited Utenzi wa Zaburi by Mathias E. Mnyampala, and re-edited at his request Utenzi wa Enjili. Later he edited Diwani tya Ustadh by Amiri A. Sudi Andanenga, and his Bahati ya Elimu ya Ushairi. These books were all published by Nnanda Mission Press. With the help of John Allen and Jan Knappert, Van Kessel was able to edit a long popular Swahili epic poem (4.584 stanzas), Utenzi wa Rasi ‘1 Ghuli, reconstructing and transcribing it from three different manuscripts, written in Arabic script. It was, and is, the longest epic poem ever published in an African language. Walter Mboya and M.M. Mulokozi appreciated the importance of it and had it printed and published by Tanzania Publishing House in 1979.