Saint Eustathios, Patriarch of Constantinople.
Eustathios was a priest of the imperial palace who was raised to the patriarchal throne of Constantinople in 1019. He governed the Church for six years with prudence and reposed in peace in 1025.
He is commemorated on May 31.
Feast day
On the New Calendar, Eustathios of Constantinople is commemorated on May 31. Churches on the Old (Julian) Calendar keep the feast on June 13 of the civil calendar.
Also commemorated on May 31

Eusebios and Charalambos
Martyr, Ευσέβιος και Χαράλαμπος
Holy Martyrs Eusebios and Charalambos, burned for their faith.
Petronilla of Rome
Holy Woman, Πετρονίλα
Saint Petronilla, virgin of Rome, honored as a spiritual daughter of the Apostle Peter.
Name days: Petronilla
Five Martyrs of Ascalon
Martyr, Πέντε Μάρτυρες εν Ασκάλωνι
The Five Holy Martyrs who suffered at Ascalon in Palestine.
Co-workers of the Apostle Paul
Apostle, Συνεργοί του Αποστόλου Παύλου
Synaxis of the holy men and women named as fellow-laborers of the Apostle Paul in his epistles.
Hierotheos the New
Hierarch, Ιερόθεος ο Νέος
Hieromartyr Hierotheos the New, who suffered under the Turks.