Columbia subject headings:
Contemplation--History--To 1500.
Philosophy and religion--History--To 1500.
Prayer--Christianity--History--Early church, ca. 30-600.
Prayer--History--To 1500.
Harvard subject headings:
Contemplation--History--To 1500.
Philosophy and religion--History--To 1500.
Prayer--Christianity--History--Early church, ca. 30-600
Prayer--History--To 1500.
Syncretism (Religion)--History--Congresses.
Princeton subject headings:
Contemplation--History--To 1500.
Philosophy and religion--History--To 1500.
Prayer--Christianity--History--Early church, ca. 30-600.
Prayer--History--To 1500.