prosperity and economic recovery. During the Yuanjia era, the Chinese developed the co-fusion process of steel manufacturing, which involved melting cast iron and wrought iron together to create steel, increasing the quality and production volume of Chinese iron. Towards the end of Emperor Wen's reign, the Xianbei state of Northern Wei began to strengthen, and decisively defeated an attempt by Emperor Wen to destroy it. Following this victory, Wei launched repeated incursions into the northern provinces, finally capturing them in 468. The economic prosperity of southern China continued after Liu Song's fall and was greatest during the succeeding Liang dynasty, which briefly reconquered the North with 7,000 troops under the command of general Chen Qingzhi. The Liang emperor, Emperor Wu, gave a grant of 400 million coins to Buddhist monasteries, indicating the amount of wealth present in the south. It was recorded that during his reign, the city of Nanjing had a population of up to 1.4 million, exceeding that of Han-era Luoyang. The Southern Dynasties' economy eventually declined after the disastrous sacking of Nanjing by the barbarian general Hou Jin. Northern Dynasties After the Xianbei conquest of Northern China, it experienced an economic recovery under the Northern Wei that was even greater than the prosperous era of Yuanjia. This came mostly under the rule of Emperor Xiaowen of Northern Wei, who introduced several reforms designed to further sinify Northern Wei, which included banning the Xianbei language and customs and promoting Chinese law, language and surnames. A new agricultural system was introduced; in the equal-field system, the state rented land to the peasant laborers for life, reclaiming it after the tenant's death. Peasants also received smaller, private plots that could be inherited. Cattle and farm tools were also rented or sold to peasants. The state also introduced the Fubing system, where soldiers would farm as well as undergoing military training. This military system was used until the Tang dynasty, and empowered Han Chinese, who comprised the majority of the army. In addition, Xiaowen strengthened the state's control over the provinces by appointing local officials rather than relying on local landowners, and paying officials with regular salaries. The capital was moved to Luoyang, in the centre of the North China Plain, which revitalised the city and the surrounding provinces. Xiaowen's reforms were very successful and lead to prosperity for north China. Under Emperor Xiaowen, the taxable population was an estimated 30