'Christopher Brennan composed the bulk of his fifteen-poem sequence The Burden of Tyre between August 1900 and May 1901, but it remained unpublished until Harry Chaplin's private edition of 1953. Prompted by the Boer war, which Brennan vehemently opposed, and dealing with it as an expression of philosophical principles, he had initially hoped to "sneak it in" to Poems 1913, to lie between The Forest of Night and The Wanderer. This indicates the weight it clearly carries, which is of a different order to that of the noisier and slighter The Chant of Doom (1916), Brennan's response to the First World War. G.A. Wilkes observed that on publication "It seems at once to have proved itself as inscrutable as the rest of Brennan's work". Yet only Wilkes and Mary Merewether have provided extended treatments of it, and much of it remains obscure. A close reading of his sources can solve some of the most seemingly intractable problems of Brennan scholarship, and Merewether's paper in particular is an invaluable resource in this regard. Yet she has missed the principle source of the Prologue, namely F.C.S. Schiller, whose philosophical work The Riddles of the Sphinx deeply influenced Brennan at this time; and so this most important poem of the sequence, as an overture announcing its chief themes and concerns, remains poorly understood. Wilkes felt that "[It] certainly is political poetry, but only intermittently is it anything more"; and Merewether that "The reading of The Burden of Tyre ... shows there to be few new ideas in it". The purpose of this paper is to provide a thorough exegesis of the Prologue in the light of The Riddles of the Sphinx, and to show that there are indeed new ideas in it, and ideas, moreover, which can throw light into some important aspects of Poems 1913, and into Brennan's response to one of his chief influences at the time.