This is the first published study of the church music of Peter Philips, who in his day was regarded as one of the greatest masters of music in Europe. Philips wrote against a background of the strife between Catholics and Protestants, and - being of the Roman persuasion - he chose to leave his native England and eventually settled at the court of the Archdukes Albert and Isabella in Brussels, where he acted as organist. This study explores the manner in which music changed from Renaissance style to that of the early Baroque.