University of Tehran Press Journal for the History of Science 1735-0573 10 1 2012 03 20 The Zoroastrian Persian Calendar in a Medieval Hebrew Treatise on The Jewish Calendar by Abraham bar Ḥiyya The Zoroastrian Persian Calendar in a Medieval Hebrew Treatise on The Jewish Calendar by Abraham bar Ḥiyya 31 53 36130 FA Ilana Wartenburg Journal Article 2013 03 09 This article exposes an analysis of the Zoroastrian Persian calendar in a 12^th century Hebrew book on the Jewish calendar (<em>Sefer ha-‘Ibbūr</em>). The Hebrew treatise was composed by the polymath Abraham bar Ḥiyya, probably in Northern France. Bar Ḥiyya depicts the structure of the Zoroastrian Persian calendar, its months and some of its festivals. He then expounds on calendrical algorithms which enable to convert between Persian and Jewish dates. Although one finds the names of some Persian months and festivals in earlier Jewish sources, Abraham bar Ḥiyya’s text not only elaborates in greater detail on these matters, but for the first time in Hebrew literature, one encounters conversion algorithms between the two calendars. This article exposes an analysis of the Zoroastrian Persian calendar in a 12^th century Hebrew book on the Jewish calendar (<em>Sefer ha-‘Ibbūr</em>). The Hebrew treatise was composed by the polymath Abraham bar Ḥiyya, probably in Northern France. Bar Ḥiyya depicts the structure of the Zoroastrian Persian calendar, its months and some of its festivals. He then expounds on calendrical algorithms which enable to convert between Persian and Jewish dates. Although one finds the names of some Persian months and festivals in earlier Jewish sources, Abraham bar Ḥiyya’s text not only elaborates in greater detail on these matters, but for the first time in Hebrew literature, one encounters conversion algorithms between the two calendars. https://jihs.ut.ac.ir/article_36130_4d9c41f00283f0368d75be229e4d3af1.pdf