Modern Hagiography
Lives of the Saints by Alban Butler.
Lives of the Saints by Sabine Baring-Gould.
The Liturgical Year by Dom Guéranger.
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 Saints, with Other Feasts of the Year, According to the Roman Calendar by Peter Ribadeneira.
“The Feast of St. Peter’s Chair at Rome” by Thomas Aubrey de Vere.
Medieval Hagiography
Breviarium Romanum – Latin & English
Art & Architecture
The Cathedra Petri in the Basilica of San Pietro in Vaticano (more here and here).
18C Libro del Compendio della Vita di tutti Santi
Warburg Institute Iconographic Database
Music
Hymns for Chair of Saint Peter
Devotions
Heortology: A History Of The Christian Festivals From Their Origin To The Present Day by Heinrich Kellner.