Abraham Bar Hiyya - Biography

Biography

Abraham bar Hiyya, great-grandson of Hezekiah Gaon is remembered in the world of mathematics for his role in the dissemination of the quadratic equation. Bar Hiyya wrote several scientific works in the fields of astronomy, mathematics, land surveying and calendar calculations. Abraham ben Chiya Albargeloni (b. 1065, d. 1136), also occupied a high position under another Mahometan prince al-Hud. He was a sort of minister of police (Zachib al-Shorta, hence Savasorda which literally means something like 'chief of police' but probably indicates a position of a courtier), and bore the title of prince. Savasorda is a Latinized degeneration of the Arabic title and scholars assume that Bar Hiyya would have obtained this title in the court of Banu Hud of Saragossa-Lerida; there is even a record of a Jewish Savasorda there in the beginning of the 12th century. Zachib al-Shorta, meaning " Chief of the Police" is a large landed proprietor was then named, "Governor" or " Nasi" as he was called in Hebrew. By his name Savasorda he is known through the works of the Middle Ages. He was held in high consideration by the ruler he served on account of his astronomical knowledge, and had disputes with learned priests, to whom he demonstrated the accuracy of the Jewish calendar. He also praised the parasitic science of astrology, and drew a horoscope of favourable and unfavourable days. Abraham Albargeloni reckoned that the Messiah would appear in the year after the Creation 5118 (1358 CE).

Benjamin of Tudela, in the 1160s, starting his famous journey to the East, traveled first from Tudela, which is to the northeast of Soria (bar Hiyya's birthplace), along the river Ebro to Saragossa and then further to Tortosa on the coast of the Mediterranean, before turning northwards along the coast, through Tarragona to Barcelona and Provence. He says of Barcelona: " Where there is a holy congregation, including sages, wise and illustrious men, such as R. Sheshet, R. Shealtiel, R. Solomon and R. Abraham, son of Chisdai".

According to Adolph Drechsler, he was a pupil of Rabbi Moshe haDarshan and teacher of Abraham Ibn Ezra. Abraham bar Hiyya is said to have been a great astronomer and wrote some works on Astronomy and Geography. One tells about the form of the earth, the elements and the structure of the spheres (Manuscripts may be in the Vatican, in Vienna and Paris); this work was printed in Basel by Oswald Schreckenfuchs, including a Latin translation. Other works included papers on astrology, trigonometry and music.

He also wrote two religious works in the field of Judaism and the Hebrew Bible: Hegyon ha-Nefesh ("Contemplation of Soul") on repentance and Megillat ha-Megalleh on the redemption of the Jewish people. Even these religious works contain scientific and philosophical speculation. His Megillat ha-Megalleh ("Scroll of the Revealer") was also astrological in nature. It claimed to forecast the messianic future

Bar Hiyya wrote all his works in Hebrew, not in Judaeo-Arabic of the earlier Jewish scientific literature, which made him a pioneer in the use of the Hebrew language for scientific purposes. He also cooperated with Plato of Tivoli in the translation of scientific works from Arabic into Latin, particularly the translation of Ptolemy's Tetrabiblos in 1138 at Barcelona.