pope - Catholicism, caliph - ?

ISLAM
List of words for the clue pope - Catholicism, caliph - ? from the crossword:
ALI OMAR PIUS ABU STPETER VICAR ESSAY ADRIAN TSAR SWAYER RULER MUSLIM MOSLEM KHALIFAH KHALIF KALIPH KALIF CALIF ARAB ALLAH
WordClue
IMAMcatholicism - priest, islam - ?
POPEIslam - caliph, Catholicism - ?
RABBIcatholicism - priest, judaism - ?
CALIPHCatholicism - pope, Islam - ?
PAPACYThe office of the pope
PASTORcatholicism - priest, protestantism - ?
PRIESTprotestantism - pastor, catholicism - ?
SHARIFOmar, actor
JUDAISMpriest - catholicism, rabbi - ?
MUHAMMADAli, boxer
RELIGIONchristianity or islam
ALEXANDERPope, writer
PRESIDENTVatican - pope, France - ?
CATHOLICISMcaliph - Islam, pope - ?
PROTESTANTISMpriest - catholicism, pastor - ?
IGGYPop, singer
ALEXANDERPope, writer