May 21 (Eastern Orthodox liturgics)
May 20 - Eastern Orthodox Church calendar - May 22
Sts Constantine and Helena, Holy Equals-to-the-Apostles.
Sts Constantine and Helena, Holy Equals-to-the-Apostles (Mosaic in Saint Isaac's Cathedral, St. Petersburg, Russia).
Stained glass window ( 1986 ) showing St Collen (Llangollen, Wales - St.Collen parish church)
Icon of the Saints of Murom.
May 20 (Eastern Orthodox liturgics)
May 19 - Eastern Orthodox Church calendar - May 21
St. Lydia of Thyatira.
St. Marcus Eremita.
Church of St. Theodore of Pavia, in Pavia.
The martyred Anglo-Saxon king Æthelberht II of East Anglia (depiction of a brass plate from Hereford Cathedral).