In the beginning of the 12th century, a Jewish man named Abu al-Munajja ibn Sha'yah was at the head of the Department of Agriculture. He is especially known as the constructor of a Nile sluice (1112), which was called after him "Baḥr Abi al-Munajja". He fell into disfavor because of the heavy expenses connected with the work, and was incarcerated in Alexandria, but was soon able to free himself. A document concerning a transaction of his with a banker has been preserved. Under the vizier Al-Malik al-Afḍal (1137) there was a Jewish master of finances, whose name, however, is unknown. His enemies succeeded in procuring his downfall, and he lost all his property. He was succeeded by a brother of the Christian patriarch, who tried to drive the Jews out of the kingdom. Four leading Jews worked and conspired against the Christian, with what result is not known. There has been preserved a letter from this ex-minister to the Jews of Constantinople, begging for aid in a remarkably intricate poetical style. One of the physicians of the caliph Al-Ḥafiẓ (1131–49) was a Jew, Abu Manṣur (Wüstenfeld, p. 306). Abu al-Faḍa'il ibn al-Nakid (died 1189) was a celebrated oculist.