In these first two decades after the founding of the empire, Harihara I gained control over most of the area south of the Tungabhadra river and earned the title of "Purvapaschima Samudradhishavara" ("master of the eastern and western oceans"). The Jaffna Kingdom, which encompassed the southern tip of India and parts of Sri Lanka; there was continual conflict with Vijayanagara and the smaller Kotte Kingdom of southern Sri Lanka. From 1336 to 1392, two courts claimed the throne of Japan. This was known as the Nanboku-chō, or the Northern and Southern Courts period. In the Northern Court, Emperor Go-Murakami claimed the throne. In the Southern Court, Emperor Kōmyō claimed the throne. In Southeast Asia, Sukhothai changed hands to a new Siamese dynasty in 1345. A Buddhist work, the "Traibhumikatha", was composed by the King of Siam in the same year. The Sukhothai Emperor also wrote a similar Buddhist work, the "Tri Phum Phra Ruang". Both works describe Southeast Asian cosmological ideas which still exist today. Life is said in these books to be divided into 31 levels of existence separated between three worlds. Angkor was in a period of decline, forced to devote much of its resources to skirmishes with the Sukhothai and Siamese, which left Champa free to attack Đại Việt and opened the way for Lopburi to spring up, all of which happened right around this year. A Buddhist colony also existed to the west in the Mon Empire, which struggled to maintain its existence in the face of the Islamic Delhi Sultanate to the west and the Mongol Chinese to the north. The Majapahit Empire, which occupied much of the Indonesian Archipelago, was ruled by empress Tribhuwana Wijayatunggadewi. During Tribhuwana's rule, the Majapahit kingdom had grown much larger and became famous in the area. Gajah Mada reigned at the time along with the empress as "mahapatih" (prime minister) of Majapahit. It was during their rule in 1345 that the famous Muslim traveller Ibn Battuta visited Samudra in the Indonesian Archipelago. According to Battuta's report on his visit to Samudra, the ruler of the local area was a Muslim, and the people worshiped as Muslims in mosques and recited the Koran.