Abraham Seneor or Abraham Senior (Segovia 1412 - 1493) was a Sephardic rabbi, banker and politician, a senior member of the Castilian hacienda (almojarife of the Castile or royal administrator). In 1492 he converted to Roman Catholicism, taking the name Ferran, Fernan or Fernando Perez Coronel or Fernando Coronel Nunez.
The Seneor family, from the 1460s, were the largest group engaged in tax farming for the Crown of Castile. The Seneor family was also involved in politics, defending the interests of artisans in the cities of central Castile. He was related to Andrés Cabrera (the steward of King Henry IV of Castile), Andrés Cabrera's wife, Beatriz de Bobadilla (lady of the Queen Isabella of Castile) and Alonso Quintanilla, Count of Accounts, to whom the Infante (crown prince) Alfonso had entrusted the establishment of a mint in Medina del Campo (a city enriched by the fairs). In 1488 Seneor became treasurer of the Holy Brotherhood (founded in 1476 and counting Quintanilla among its members).
His position at court was so important, it was not limited to his duties as the kingdom's most important tax farmer. In 1469 he played a major role in securing the marriage of the Infanta Isabella of Castile to Ferdinand of Aragon, including providing the betrothal gifts. In 1473 he had a hand in the reconciliation between Isabella and her estranged brother Henry IV, and, in 1474, in providing the Alcázar of Segovia (whose warden was Andrés Cabrera) as a place for Isabella to hide following the death of her brother, the king. Isabella had such confidence in Seneor that, in gratitude for his services, she endowed him with a lifetime pension of 100,000 maravedis, confirmed in 1480 at the behest of the royal confessor Hernando de Talavera. Seneor was appointed chief justice of the Jewish community of Segovia, (often clashing with converted Jews and their families) 12 and rab do la corte (court Rabbi or chief rabbi of Castile); an office for which, like many of his predecessors, the Jewish religious authorities thought him unqualified. He was so respected by the Jewish grandees, however, that the Cortes of Toledo in 1480 presented him with 50,000 maravedis. He was a close friend of Isaac Abravanel, whom he worked with in tax collection. In the War of Granada Seneor and Abravanel played a valuable role both in raising taxes and provisioning Isabella's army. They also supported Columbus's efforts to secure Isabella's patronage for the proposed transatlantic expedition of Christopher Columbus.