The complicated series of disputes which followed the York election of 1140–1 is familiar in broad outline to all students of the period. From a small beginning the strife came to involve almost every person of importance in England, and many on the Continent, and lasted, in its ramifications, for some twenty years. Yet the history of this controversy, though it could not fail to receive some notice in any detailed account of the times, has not hitherto been set out in full with complete accuracy. This failure has been due in part to the nature of the records, which are scattered among English chronicles, papal documents and Cistercian sources, and can only be fully used by one who has them all before his eyes simultaneously; many of those who have treated the episode obiter have failed thus to assemble them with completeness. In part also it has been due to gaps in the evidence at more than one crucial point, which have thrown all historians back upon conjecture. These gaps, in part, still exist, but it so happens that within the last few years a number of independent studies have reconstructed much of the narrative that was hitherto dark, and some important documents have come to light; it is therefore possible to arrive at something approaching to a clear view of the whole business.