What is "sergestus"

In Greco-Roman mythology, Sergestus was a Trojan friend of Aeneas. He was the ancestor of gens Sergia, a famous Patrician family of which Catilina was a member.

In Virgil's Aeneid, during a funerary ship race Aeneas gives to Sergestus a Cretan slave girl named Pholoe in gratitude for saving both ship and crew.

Sergestus also appears as a minor character in Christopher Marlowe's play Dido, Queen of Carthage.