Mykonos only knew three things growing up.
His father was a teacher named Cygnus at the School of Athens
He was named after a small island created by Herakles from Giant's testicles.
He had to call his father Daska.
When he was four, he asked Daska where his mother was. Daska responded with a shrug and said.
"She's where she is not."
Mykonos decided his father was an idiot.
The woman who managed the orphanage would know, so Mykonos asked her. She looked at the small boy and promptly laughed at him.
"Your mother is dead whelp."
Mykonos cried for a mother he had never known.
The woman who ran the orphanage nearly choked to death on an olive at the evening meal, only the intervention of a manservant saved her. Then she slipped in the olive oil and fell to brain herself on a bust of Athena. Mykonos saw it all and also saw that Athena -who normally looked so severe was smiling. The woman saw Mykonos' smile and flew into a rage. She came at him with a strap only to step in the same spilled oil, falling flat on her face at his feet. She got to her knees and was about to grab the boy when an owl flew in and dropped a mutilated mouse on her upturned face. She screamed for a few beats, gasping in horror at the mouse before looking wide-eyed at Mykonos. Whatever she saw terrified her and she fled the orphanage never to be heard from again.
So Cygnus received his 5-year-old son following that occurrence from the orphanage with instructions never to bring Mykonos there again. Cygnus spent the no time in preparing for a trip, taking his son back to Thessaly to the court of Peleus where he paid a midwife to take care of his son and returned to Athens. Cygnus and Mykonos never saw each other again, living.
Mykonos spent the rest of his all too brief youth in the palace of Peleus following his adoptive mother about until age seven when she presented him to the Myrmidons for a life of training and soldiering.