- Costanzo of Perugia
First bishop of Perugia, Italy at age 30. He evangelized his people, cared for the poor, and lived a simple life that shamed the ruling classes. Imprisoned, tortured and martyred with many of his flock in the persecution of Marcus Aurelius.
- Book of Saints, by the Monks of Ramsgate
- For All The Saints, by Katherine Rabenstein
- Our Sunday Visitor’s Encyclopedia of Saints