A fên-ssŭ is a Buddhist monastery built by the side of a grave, a place to offer services to the buried and as a guardian of the grave.In the Sung period following 1044 imperial permission was required to build a fên-ssŭ. The practice seems to have started during the reign of Jen-tzung 仁宗, the earliest recorded request being that made by Fang Chung-vent 范仲淹 in 1044 with regard to Pai-yün ssŭ 白雲寺 in Suchou 蘇州. The advantages to be gained from the constitution of fên-ssŭ prompted officials of all grades to seek the authority to build them. By 1059 the number of requests had risen so high that the court was forced to limit the right to only the highest officials Therefore following 1059 only those officials who had risen to the ranks of tsai-hsiang 宰相, ts'an-chih chêng-shih 参知政事, shu-mi shih 枢密使, or shu-mi fu-shih 枢密副使 could require a fên-ssŭ. Middle and low-ranking officials who did not qualify then built privately the fên-an 墳庵. There were also those who for religious reasons built Taoist temples instead, such as in the case of Ou-yang Hsiu 欧陽脩. One reason for the popularity of building the fên-ssŭ was economic advantage. That is the fên-ssŭ and its properties were exempted from taxation. Moreover, Sung scholar-officials tended to live away from the ancestral village, and, since there was no guarantee that the kinsmen who remained in the village woluld continue to flourish, they felt more comfortable entrusting the care of the ancestors' graves to fên-ssŭ. The fên-ssŭ as an institution was discontinued in the Yüan, but privately built fên-an, both Buddhist and Taoist, continued to flourish. During the Ming, however, the fên-an disappeared, and farms attached to the grave, called mu-chuang 墓荘 or mu-t'ien 墓田 took their place. The tenant of the farms were charged with the responsibility of looking after the graves. The main reason for this change was the general acceptance of the Wên-kung chia-li 文公家礼 by Chu Hsi 朱熹.