It is generally believed that Ame Pal (A-ma-dpal in Tibetan) was the founder king of Lo in 1380. The ancestry of the present Mustang raja can be traced 25 generations back to Ame Pal. Ame Pal, or perhaps his father, conquered a large part of the territory in the upper Kali Gandaki and was responsible for the development of the city of Lo Manthang and many gompas. To the west, the Malla Empire declined and split into numerous petty hill states. By the 18th century, Jumla had consolidated and reasserted its power. In an effort to develop their domain as a trading centre and to obtain Tibetan goods, the rulers of Jumla turned their attention eastward. In the mid-18th century they assumed control over Lo, from which they extracted an annual tribute.
When he ascended the throne in 1762, Prithvi Narayan Shah began to consolidate what is present-day Nepal. At the time of his death, the kingdom extended from Gorkha eastward to the borders of Sikkim. His descendants directed their efforts westward and by 1789, Jumla had been annexed. The Gorkha armies never actually entered Lo; they recognised the rule of the Mustang raja. Although Mustang became part of Nepal, the raja retained his title and Lo retained a certain amount of autonomy. Lo maintained its status as a separate principality until 1951. After the Rana rulers were overthrown and King Tribhuvan re-established the rule of the Shah monarchs on 15 February, 1951, Lo was more closely consolidated into Nepal. The raja was given the honorary rank of colonel in the Nepalese army. During the 1960s, after the Dalai Lama had fled to India and Chinese armies established control over Tibet, Mustang was a centre for guerrilla operations against the Chinese. The soldiers were the Khampas, Tibet's most fearsome warriors who were backed by the CIA (some Khampas were secretly trained in the USA). At the height of the fighting there were at least 6000 Khampas in Mustang and neighbouring border areas. The CIA's support ended in the early 1970s when the USA, under Kissinger and Nixon, initiated new and better relations with the Chinese. The government of Nepal was pressed to take action against the guerrillas and, making use of internal divisions within the Khampa leadership, a bit of treachery, and the Dalai Lama's taped advice for his citizens to lay down their arms, it managed to disband the resistance without committing to action the 10,000 Nepalese troops that had been sent to the area.
Though Mustang was closed, the government allowed a few researchers into the area. Toni Hagen included Mustang in his survey of the entire kingdom of Nepal, and the Italian scholar Giuseppi Tucci visited in the autumn of 1952. Professor David Snellgrove travelled to the region in 1956 but did not visit Lo Manthang. Longtime Nepal resident Barbara Adams travelled to Mustang during the autumn of 1963. The most complete description of the area is Mustang, the Forbidden Kingdom, written by Michel Peissel who spent several months in the area in the spring of 1964. Dr Harka Bahadur Gurung also visited and wrote about upper Mustang in October 1973. A number of groups legally travelled to upper Mustang during the 1980s by obtaining permits to climb Bhrikuti peak (6364 metres) south-east of Lo Manthang. Other than a few special royal guests, the first legal trekkers were allowed into Mustang in March 1992 upon payment of a high fee for a special trekking permit.
The trek to Lo is through an almost treeless barren landscape. Strong winds usually howl across the area in the afternoon, generally subsiding at night. Being in the rain shadow of the Himalaya, Lo has much less rain than the rest of Nepal. During the monsoon the skies are cloudy and there is some rain. In the winter there is usually snow; sometimes as much as 30 or 40 cm accumulates on the ground.
In Lo itself the countryside is similar to the Tibetan plateau with its endless expanses of yellow and grey rolling hills eroded by wind. There is more rain in the lower part of upper Mustang and the hills tend to be great red fluted cliffs of tiny round stones cemented together by mud. Villages are several hours apart and appear in the distance almost as mirages; during the summer season, after the crops are planted, they are green oases in the desert-like landscape.
The trek to Lo is through an almost treeless barren landscape. Strong winds usually howl across the area in the afternoon, generally subsiding at night. Being in the rain shadow of the Himalaya, Lo has much less rain than the rest of Nepal. During the monsoon the skies are cloudy and there is some rain. In the winter there is usually snow; sometimes as much as 30 or 40 cm accumulates on the ground.
In Lo itself the countryside is similar to the Tibetan plateau with its endless expanses of yellow and grey rolling hills eroded by wind. There is more rain in the lower part of upper Mustang and the hills tend to be great red fluted cliffs of tiny round stones cemented together by mud. Villages are several hours apart and appear in the distance almost as mirages; during the summer season, after the crops are planted, they are green oases in the desert-like landscape.
Because of the cold and snow, most of the population departs from Lo on trading expeditions during the winter. The trekking season, therefore, is from late March until early November. The trek does not go to extremely high elevations, but the cold, dust and unrelenting afternoon winds can make the trek less pleasant than other treks in Nepal.