Blood on the Cross outlines the history of that extraordinary period during which the Muslims flourished and perished in southern Spain. It includes a study of the origins of and interaction between the Unitarian and Trinitarian Christians in Spain – and traces the almost total annihilation of the Unitarian Christians at the hands of the Trinitarian church by means of the Mediaeval and Spanish Inquisitions. Without this analysis, it is virtually impossible to understand how it was that the inhabitants of the Iberian peninsula in the 8th century CE embraced Islam so readily and rapidly – and how it was that the Jews and Muslims of Spain in the 16th century CE were either exterminated by the Spanish Inquisition or forced to flee for their lives.