Heliodorus of Emesa, third or fourth century CE, is the name this site attaches to a Greek writer from Emesa. The Suda’s bishop-story is a later report and a possible mix with another Heliodorus.
What this site holds is the Aethiopica (Αἰθιοπικά), a complete Greek διήγημα in ten books, and Epigrams travelling under the same name in the Greek Anthology. The διήγημα names Theagenes and Chariclea. Tasso, Cervantes, and Sidney are later vernacular, not this corpus. It is a Greek book here, not a Renaissance sourcebook.
Also published as PDF.