The site is at the top of a 480 metre high basalt mountain, the Hasunger Berg. In 1074 a monastery was built, on the authority of Siegfried I, Archbishop of Mainz, over the grave of the hermit Heimerad (d. 1019), who had had a little chapel and hermitage here. The historian Lambert of Hersfeld (d. circa 1088) was possibly abbot of Hasungen towards the end of his life. The monastery existed until the Reformation, introduced in Hesse in 1527 by Philipp I of Hesse. Until then the abbey had been a centre of pilgrimage because of Heimerad, commonly venerated as a saint.