Mohammed Zahir Shah, Nadir Shah's 19-year-old son, succeeded to the throne and reigned as King from 1933 to 1973. The tribal revolts of 1944–1947 saw King Zahir's reign challenged by Zadran, Safi, Mangal, and Wazir tribesmen led by Mazrak Zadran, Salemai, and Mirzali Khan, among others, many of whom were Amanullah loyalists. Close relations with the Muslim states Turkey, the Hashemite Kingdom of Iraq and Iran/Persia were also pursued, while further international relations were sought by joining the League of Nations in 1934. The 1930s saw the development of roads, infrastructure, the founding of a national bank, and increased education. Road links in the north played a large part in a growing cotton and textile industry. The country built close relationships with the Axis powers, with Nazi Germany having the largest share in Afghan development at the time, along with the Kingdom of Italy and the Empire of Japan.