At the beginning of the twelfth century the city of Pisa led an expedition against the Arabs in the Balearic islands in the guise of a crusade. Soon after the return of the victorious Pisans to their city an epic, approximately 3,500 hexameters in length, was written in Latin recording their glorious deeds. This poem, the Liber Maiorichinus, is heavily indebted to the epics of classical Rome for its imagery, and to the major classical epicists, Vergil in particular, for its language. The wealth of detail found in the poem concerning the expedition's route, its course of action and the characters who participated in it suggests that the author himself was a member of the expedition. Both of these aspects of the poem are discussed in the introduction to this thesis. The poem was revised soon after its composition; the revision, which was authorial, increased the classical content of the poem and added more detailed information about the expedition. A Pisan tradition maintains that the epic was composed by Henry of Pisa. Of the three manuscripts which contain a text of the Liber Maiorichinus, one, the oldest, contains no indication of the author's identity; the other two manuscripts suggest that Laurentius Veronensis was the author. Writers at the end of the last century and in the first twenty years of this century concentrated their research upon the identity of the poem's author. An outline of their conclusions is included in this thesis. The greater part of this thesis consists of a critical edition of the Liber Maiorichinus with a translation into English. None of the previous editions of the poem are critical ones, and no translation has been available in any language.