Task: Question Answering
Input (English): Passage: Professor John Oldman is packing his belongings onto his truck, preparing to move to a new home. His colleagues show up to give him an impromptu farewell party: Harry, a biologist; Edith, an art history professor and devout Christian; Dan, an anthropologist; Sandy, a historian who is in love with John; Art, an archaeologist; and his student Linda.
As John's colleagues press him to explain the reason for his departure, he picks up from a reference to Magdalenian cultures by Dan and slowly, and somewhat reluctantly, reveals that he is a prehistoric caveman himself from that precise period. He states that he has lived for more than 14 millennia, and that he relocates every ten years to keep others from realizing that he does not age. He begins his tale under the guise of a possible science-fiction story, but eventually stops speaking in hypotheticals and begins answering questions from a first-person perspective. His colleagues refuse to believe his story but accept it as a working hypothesis in order to glean his true intentions. John relates he was a Sumerian for 2000 years, later a Babylonian, and eventually went East to become a disciple of Buddha. He claims to have had a chance to sail with Columbus (admitting that at the time he still believed the earth was flat) and to have befriended Van Gogh (one of whose original paintings he apparently owns, a gift from the artist himself). 
Question: What is the full name of the person who said that they once believed the Earth was flat?
Output (English): John Oldman.