One of the most obscure and poorly illuminated pages of the early dynastic history of the Seleucids is the events of the mid-260s BC related to the death of Prince Seleucus, the eldest son of Antiochus I. The purpose of this study is to present the most probable version of the circumstances that led to the premature death of Prince Seleucus on the basis of consideration and comparison of all known facts. After analyzing all the known sources, it is assumed that the prince fell victim to a planned and phased action, which is supported by the gradual promotion of the tsar's youngest son, Antiochus II, as a successor. This is especially clearly reflected in one of the cuneiform texts (AION Suppl. 77.15), indicating a "double co-government" in the Seleucid empire. The main reason for the elimination of Seleucus was precisely personal motives. At the same time, it is quite likely that officially, in order to give the case legitimacy, the tsarevich was accused of some malice against his father and on this basis was executed. Keywords: The Seleucid Kingdom, Institute of Co-government, Prince Seleucus, Antiochus I. page 19The history of most Hellenistic monarchies, as is well known, was marked by numerous court intrigues, conspiracies and usurpations of power, often leading to bloody feuds within the ruling houses and becoming the main cause of the death of some of them1. As a rule, the information that has come down to us about such facts is fragmentary and contradictory. The secrets of the Hellenistic court were not always publicized, and if they did, the version that was favorable to the winning side was known. This is exactly the case with the subject of this article: the events of the mid-260s (hereinafter referred to as BC) related to the death of Prince Seleucus, the eldest son of Antiochus I, can be regarded with good reason as one of the most poorly illuminated and little-known pages of the early dynastic history of the Seleucids. The main problem faced by the rese ... Read more