Abaye ben Natronai Kohen Ṣedeq, Gaon of Pumbeditha

According to Sherira Gaon, Abbaye was not his personal name, but Nachmani, after his grandfather. His father had died before Abbaye was born, and his mother died in child-birth. So the orphan was brought up by his uncle Rabbah bar Nachmani. Rabbah did not want to call his nephew Nachmani, which was the name of his father; he therefore called him "Abbaye," meaning, "my father.

Of Abbaye's personal life we know but little. He seems to have been quite poor, for when his widow asked the Beth-Din (court) to grant her a pension for bread and wine, they answered that as far as they knew there was never any wine at Abbaye's table. Yet Abbaye never wished to receive gifts, and only on Erev Yom Kippur he accepted gifts, being a Kohen, a descendant of Eli the high priest.

Once, when an ass of Abbaye went astray and was found by the Samaritans, Abbaye sent a message to them, "Return the ass to me; it is mine." They replied, "Give us some identification marks." Abbaye replied, "It has a white belly." The Samaritans sent the ass to him saying, "If you were not Nachmani we would not have returned the ass to you. What kind of identification is this? Haven't all asses white bellies?!" (Gittin 45a).

Abbaye had a childhood friend, with whom he grew and studied. His name was Rava. Later Rava went to Mechoza and Nehardea to study, but they were almost inseparable in their discussions of various points of law. The Talmud is full of their teachings which are quoted either jointly in their names, such as "Abbaye and Rava both say," or in discussion, such as "Abbaye questions Rava," or "Abbaye explained to Rava" or "Abbaye and Rava differed in their opinion on..." Thus "the discussions of Abbaye and Rava" became very famous. Yet, despite Abbaye's great position, the sages who decided whose opinion to follow ruled that Rava's opinions were valid against Abbaye's in all but six cases, which are well known to Yeshivah students by the abbreviation YaAl KaGaM.