May 18 (Eastern Orthodox liturgics) - Wikipedia
https://en.wikipedia.org/wiki/May_18_(Eastern_Orthodox_liturgics)
May 17—Eastern Orthodox Church calendar—May 19. All fixed commemorations below ... Potamon (Palæmon), Bishop of Heraclea in Egypt, and Confessor (340); The Holy clergy and lay martyrs massacred under Emperor Valens (364-378) ...
OrthodoxWiki
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Dec 20, 2016 - May 18 2017: ... Heraclea in Egypt, and Confessor (340); The Holy clergy and lay martyrs massacred under Emperor Valens (364-378); Martyrs ...