The fourth chapter of Massekhet Kiddushin, Perek Asarah Yuhasin, began on daf 69a with a Mishna that discussed the levels and characteristics of the families that returned to Israel from Bavel at the beginning of the Second Temple period. Specifically, the Mishna focused on which types of families were permitted to marry other families, and which were limited regarding the families that they were allowed to marry.
Our daf tells a lengthy story that describes an incident where someone from Neharda’ah who was visiting Pumbedita acted in an inappropriate manner, insulting Rav Yehuda bar Yehezkel, who excommunicated him. Upon hearing that the visitor also habitually accused others of being from a family of slaves, Rav Yehudah bar Yehezkel ruled that that person should be given the status of a slave. Following this incident, the man from Neharda’ah invited Rav Yehuda bar Yehezkel to a din Torah – a court hearing – in the court of Rav Nahman in Neharda’ah.
After some introductory conversation, Rav Nahman asked Rav Yehuda bar Yehezkel to explain why he had declared this man to be an eved. Rav Yehuda bar Yehezkel explained that it was a teaching of Shmuel that “Kol haposel, be-mumo posel – someone who makes accusations about others will invariably project his own problem on others.” Rav Nahman objected that Shmuel only said that as a matter of psychology and suspicion; he did not mean that the person should be declared as such.
At that point, the person himself announced that his ancestry was impeccable – he was from the family of the Hasmonean kings! At that point, Rav Yehuda bar Yehezkel declared that he was certainly a slave, since Shmuel’s tradition was that all who claimed to be descendants of the Hasmonean dynasty were slaves.
King Herod, who married Miriam the Hasmonean, was himself from a family of slaves. He murdered all of the other Hasmoneans (and eventually Miriam, as well) so that he would have no challengers to the throne. While Herod’s grandson, King Agrippas also married a woman from the Hasmonean family, his children either intermarried, or married within the family, leading to the tradition that all descendants of the Hasmoneans were slaves.