Telesto was one of the three-thousand Okeanides (daughters of Okeanos & Tethys). Her name translates to "success." The fact that her name means success leaves no question to why she is the goddess of success and accomplishment. She was probably one of the Nephelai and an ethereal goddess. Telesto is mentioned in Homer's Theony (p. 358) as "wearing a yellow peplos"
Okeanos & Tethys