When did Dj Tiesto start calling himself Tiesto?

It used to be DJ Tiësto, but he changed it to Tiësto later on. I suppose everybody already knows he’s a DJ so it wasn’t really needed, and just Tiësto sounds better IMHO.

See also Wikipedia: “Although he has used many aliases in the past, he is best known for his work as DJ Tiësto.[3] On his latest productions, however, he has dropped the “DJ” label[4] and is now known simply as “Tiësto”, an alias which is a twist on his childhood nickname.”