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Pope Callistus I - http://www.newadvent.org/cathen/03183d.htm
Martyr, d. about 223. Also known as Callixtus or Calixtus. |
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Callistus I - http://saints.sqpn.com/saintc36.htm
Illustrated profile, with links. |
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Catholic Online: St. Callistus I - http://www.catholic.org/saints/saint.php?saint_id=31
Hagiography, by Terry Matz. |
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St Calixtus, or Callistus, Pope, Martyr - http://www.ewtn.com/library/MARY/CALLIXTU.htm
From Butler's Lives of the Saints. |
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Calixtus I - http://encyclopedia.jrank.org/CAL_CAR/CALIXTUS_I.html
Biographical profile of the third-century pope, in the 1911 Encyclopędia Britannica. |