13 August – Saint Cassian of Immola

Annus Dierum Sanctorum
Aversio parvulorum interficiet.
The turning away of little ones shall kill.
Proverbs 1.32
Sagittae parvulorum factae sunt plagae.
The arrows of children are wounds.
Psalm 63.8

Modern Hagiography

Bibliotheca Sanctorum

Martyrologium Romanum

Roman Martyrology

Lives of the Saints by Alban Butler.

Lives of the Saints by Francis Weninger.

Lives of the Saints by Sabine Baring-Gould.

Character Calendar

Light from the Lowly volume II by Francis Butina.

Short Instructive Sketches from the Lives of the Saints 

The Lives of Saints, with Other Feasts of the Year, According to the Roman Calendar by Peter Ribadeneira.

Medieval Hagiography

BHL, Supplement 

Acta Sanctorum

The Cult of Saints in Late Antiquity Database

“The Passion of St. Cassian of Forum Cornelii” in the Liber peristephanon of Prudentius.

Art & Architecture

Index of Medieval Art

BeWeB

Guide to Christian Iconography: Images, Symbols, and Texts 

Kornbluth Photography Historical Archive

San Cassiano, Venice

Post-Biblical Saints Art Index (not John Cassian)
Saints and their Attributes

Sacred and Legendary Art volume II by Mrs. Jameson.

A Handbook of Christian Symbols and Stories of the Saints as Illustrated in Art by Clara Erskine Clement.

Saints and their Symbols: A Companion in the Churches and Picture Galleries of Europe by E. A. Greene.

The Saints in Art by Joseph Maria von Radowitz.

Emblems of Saints by Which They Are Distinguished in Works of Art by F. C. Husenbeth.