Columbia subject headings:
Harvard subject headings:
Byzantine Empire--History--Alexius I Comnenus, 1081-1118.
Christianity and other religions--Islam
Crusades--First, 1096-1099
Crusades--First, 1096-1099--Participation, Italian.
Crusades--First, 1096-1099--Social aspects.
Islam--Relations--Christianity
Princeton subject headings:
Crusades--First, 1096-1099.