July 13 in Eastern Orthodox liturgical calendars is a feast day and a day of commemoration of saints and martyrs. Although some Orthodox churches use the Revised Julian Calendar and others use the traditional Julian calendar, the fixed commemorations for their respective July 13 are broadly the same, no matter which calendar is used.
Synaxis of the Holy Archangel Gabriel.
Martyr Serapion, under Severus (c. 205) (see also: July 12)
Martyr Marcian of Iconium (258) (see also: July 11)
Venerable Abbess Sarah of Scetis (370)
Martyr Golinduc, in holy baptism Mary, of Persia (591) (see also: July 12)
Venerable Stephen the Sabaite (Stephen the Hymnographer) (794 or 807)
Saint Julian of Le Mans, Bishop of Cenomanis (Le Mans) in (Gaul) (1st or 3rd century) (see also: January 27 - West)
Saint Dogfan (Doewan), martyred by heathen in Dyfed in Wales where a church was dedicated to him (5th century)
Saint Just of Penwith, monk, of Cornwall (5th century)
Saints Eugene, Bishop of Carthage, Salutaris, Archdeacon of Carthage, Muritta the Deacon, and Companions, Confessors (505)
Venerable Abbess Mildred of Thanet, Abbess of Minster-in-Thanet Convent (c. 733) (see also: February 20)
Saint Turiaf of Dol (Turiav, Turiavus), successor of St. Samson as Bishop of Dol in Brittany (c. 750)
The holy Five Martyrs of Alamannia who suffered in Cyprus:
Heliophotus, Epaphrodites, Ammon, Auxouthenius, and Euthenius, monks, of Cyprus (12th century)
Saint Onesiphorus, born in Constantinople, ascetic in Cyprus and Wonderworker.
Holy Children-Martyrs Of Jastrebarško and Sisak (1942)
Icon of the Most Holy Theotokos "Axion Estin" ("It is Truly Meet"). (see also: June 11)