Chronology of the Events of the Samarqand “Observatory and School” Based on some Old Persian Texts: a Revision

In the 9th century c. A.H/15 c. A.D Ulugh Beg, the son of Shāhrukh, became the ruler of Samarqand and invited a group of astronomers and mathematicians to Samarqand to establish a school (madrasa) and observatory there. During the last century some historians of science dealt with the details of the events which occurred in that scientific circle and tried to identify the dates of the events concerning this circle.

It seems that some of these events have been neglected, or incorrectly dated by them. It mainly goes back to two reasons. The first one was the differences in citations between historical sources and the second one was the way in which the dates can be interpreted.

The present article follows three main aims. First of all, it provides a time table of the known events related to the scientific circle and observatory. Secondly it deals with the dated events in various historical Persian texts, based on possible different translations and interpretations. Thirdly we will discuss the possible different dates given by some researchers on these events and will distinguish those which may be more authentic. It is noteworthy to say that the Persian texts concerning the Samarqand School and Observatory are translated into English in this article for the first time.