13 May – Saint John the Silent

Menologion of Basil II (about)
Compositions artistiques (about)
The Book of Saints

Modern Hagiography

Roman Martyrology

Sanctorale Catholicum

Lives of the Saints by Alban Butler.

Lives of the Saints by Sabine Baring-Gould.

Character Calendar 

Pictorial Lives of the Saints 

La vie des saints 

Our Birthday Bouquet Culled from the Shrines of the Saints and the Gardens of the Poets by Eleanor C. Donnelly.

Pictorial Half Hours with the Saints by Auguste François Lecanu.

The Lives of the Fathers of the Eastern Deserts by Richard Challoner.

Medieval Hagiography

Acta Sanctorum

The Cult of Saints in Late Antiquity Database

Cyril of Scythopolis’s Life of Saint John the Silent (in Greek)

Art & Architecture

Wikimedia Commons

Saints and their Attributes

Lives and Legends of the Great Hermits and Fathers of the Church, with Other Contemporary Saints by Mrs. Arthur Bell.

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.

13 May – Saint Servatius of Tongeren

Stained Glass Panel
Scènes de la vie de saint Servais de Tongres
Our Lady with Child venerated by St. Servatius
S. Servais, évêque (St. Servatus, Bishop), May 13th, from Les Images De Tous Les Saincts et Saintes de L'Année (Images of All of the Saints and Religious Events of the Year), Jacques Callot (French, Nancy 1592–1635 Nancy), Etching; second state of two (Lieure)
Les Images De Tous Les Saincts et Saintes de L’Année
The Book of Saints

Modern Hagiography

Roman Martyrology

Sanctorale Catholicum

Lives of the Saints by Alban Butler.

Lives of the Saints by Sabine Baring-Gould.

Short Lives of the Dominican Saints 

Medieval Hagiography

BHL, Supplement

Acta Sanctorum

The Cult of Saints in Late Antiquity Database

Art & Architecture

Index of Medieval Art

Portail Biblissima

Belgian Art Links and Tools

Europeana

Warburg Institute Iconographic Database, Golden Legend illustrations

Medieval Religion Listserv – 2016 Dillon.

The Church of Saint Servatius in Maastricht – Treasury, About the city of Tongeren

The Church of Saint Servatius at Quedlinburg Abbey

Post-Biblical Saints Art Index
Saints and their Attributes

Lives and Legends of the Great Hermits and Fathers of the Church, with Other Contemporary Saints by Mrs. Arthur Bell.

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.

Music

Cantus: A Database for Latin Ecclesiastical Chant