Spain had recently seen the marriage of Isabel de Castilla and Fernando de Aragón, the Catholic Monarchs. Under their rule began the centralization of power in Spain, then fragmented by individual governance of its many regions. The monarchs desired to conquer the kingdom of Granada, which at that time was Muslim. Don Isaac Abravanel saw this as an opportunity and became a financier at the court. His son, Judah, joined him in service to the Catholic Monarchs in 1484 as personal doctor to the royal family.