On his last day in Greece, Ambrogio asked Selene to marry him and return with him to Italy. She agreed. He said he would make the preparations then meet her at dawn the next morning at their meeting spot outside the temple.
Apollo, the sun god, had been watching. He himself had taken a liking to the beautiful Selene and was enraged that Ambrogio would come to his temple and take one of his maidens away. At sunset that night, Apollo appeared to Ambrogio and cursed him so that from that day forth a mere touch of Apollo's sunlight would burn Ambrogio's skin.
Ambrogio was distraught. He was set to leave with Selene in the morning, but he would not be able to meet her at sunrise as he promised because of the curse. Having nowhere else to turn, he ran to a cave that led to Hades for protection. Hades, god of the underworld, listened to his tale and made him a deal - if he could steal the silver bow of Artemis and bring it back, Hades would grant him and Selene protection in the underworld. The deal specified that Hades would give Ambrogio a magical wooden bow and 11 arrows to hunt with. He was to offer his hunting trophies to Artemis in order to gain her favor and steal her silver bow. As collateral, Ambrogio had to leave his soul in Hades until he returned with the bow. Should he return without the silver bow, he would have to live in Hades forever, never to return to Selene. Having no other choice, Ambrogio agreed.
He had no way to contact Selene. He had parchments, but no writing implement, so he took his bow and arrow and killed a swan. Using its feather as a pen, and its blood as the ink, he wrote her a note explaining that he could not meet with her but would find a way for them to be together. He left the note in their meeting place and ran off to find a place to hide from the sunlight.
Naturally, Selene was devastated when she found the note, but she kept working at the temple as she did not want to anger Apollo any further. The next morning, Selene went back to the meeting place, but once again Ambrogio was not there. She saw another piece of parchment with writing in blood on it. It was a love poem from Ambrogio.