The kingdom was closed to foreigners, with rare exceptions, until 1992. Professor David Snellgrove and Italian scholars Giuseppe Tucci and Michel Peissel travelled to Mustang in the 1950s. Their tales of a Tibetan kingdom in an arid and locked off from the rest of the world ignited the interest in Mustang District. The first westerner in Mustang was Toni Hagen, Swiss explorer and geologist, who visited the Kingdom in 1952 during one of his travels across the Himalayas. French Michel Peissel is considered the first westerner to stay in Lo Manthang, during the first authorised exploration of Mustang in 1964.