The history of vampires begins with a single vampire who created the others. Until recently, we had little idea of how the first vampire came to fruition.
The answer actually lay in a set of age old documents called the Scriptures of Delphi. The Scriptures of Delphi are a collection of writings that included the story of the very first vampire, who started out as a human. His name was Ambrogio, and he was an Italian-born traveller who found himself in Delphi, Greece. Through a series of blessings and, of course, curses found himself transformed into the very first vampire.
The story tells of the Greek god Apollo who, while enraged, cursed Ambrogio so that his skin would burn if it were to touch sunlight again. Ambrogio's run of bad luck continued when he ended up losing his soul to Hades. In turn, Artemis, the goddess of hunting and the moon, made it so that Ambrogio's skin would burn if he touched silver. Artemis, taking pity on the wretched man, gave him the gift of immortality. He would carry his curses—his skin burned by silver or sunlight—but he would remain immortal. Artemis also gave him the strength and the speed to become a skilled hunter and also gave him the ability to suck blood.
Ambrogio hunted swans and used their blood as ink for love letters and poems to Selene, his lady.
While this may be considered strange nowadays, it wasn't at all in uncommon in Ancient times to use what you hunted in any capacity you needed it.