4 May – Saint Pelagia of Tarsus

Menologion of Basil II (about)
Ste. Pélagie, vierge et martyre (St. Pelagia, Virgin and Martyr), May 4th, 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

Dictionary of Saintly Women

Lives of the Saints by Sabine Baring-Gould.

Medieval Hagiography

Acta Sanctorum

The Cult of Saints in Late Antiquity Database

Art & Architecture

Index of Medieval Art

Saints and their Attributes

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.

4 May – Saint Helenus

Commanding Crocodile in Morgan Library Vitae Patrum
Saint Hélein et l’onagre & Saint Hélein et le crocodile (France, Paris. Bibliothèque nationale de France, Département des manuscrits, Français 51 f.158)
Annus Dierum Sanctorum
Non potestis mensae Domini participes esse, et mensae daemoniorum.
You cannot be partakers of the table of the Lord, and of the table of devils.
1 Corinthians 10.21

Medieval Hagiography

BHL, Supplement

Art & Architecture

Index of Medieval Art

Portail Biblissima

Warburg Institute Iconographic Database

Morgan Library Vitae Patrum, Folio 47r & 47v (see above)

Caractéristiques des saints dans l’art populaire by Charles Cahier – ane (onagre), crocodile, ermitage.

4 May – Saint Cyriacus of Jerusalem (or Ancona)

Menologion of Basil II (about)
The Book of Saints

Modern Hagiography

Roman Martyrology

Lives of the Saints by Sabine Baring-Gould.

Medieval Hagiography

BHL, Supplement

The Cult of Saints in Late Antiquity Database

The Golden Legend

Art & Architecture

Index of Medieval Art

Portail Biblissima

BeWeB

Ancona Cathedral

Altar Frontal from Durro

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