Pakmodrupa Jangchub Gyeltsen of the Lang clan successfully challenged the Sakyas over the right to administer Mongol-ruled Tibet. By 1368, the Pakmodrupa rule was centralized enough to survive the fall of the Yuan Dynasty and take control of Tibet. The new government enacted a code of law and instituted a system of administration centered on newly created forts (dzong). Tsongkhapa was born in 1357 in Amdo and the Kagyu polymath and historian Go Lotsawa Zhonnu Pel was born in 1392 in Chonggye. The great Nyingma scholar Longchenpa, born in 1308, wrote the works that would later be collected into the Seven Treasures, systemizing for the first the teachings of what would become known as the Nyingma tradition. Zhang Sherab Lama established his kingly rule in Mustang.