Sentence:  St. Gregory, being himself a Bishop of Rome, and writing against the title of "Universal Bishop", saith thus, "None of all my predecessors ever consented to use this ungodly title; no bishop of Rome ever took upon him this name of <WSD>singularity</WSD>." 
Meaning of the word marked with <WSD> tags:  Possession of a particular or exclusive privilege, prerogative, or distinction.