The Isabella and Ferdinand Trilogy, book 2: Spain for the SovereignsJean Plaidy1960

Married to Ferdinand after continual fears and disappointments, Isabella triumphed over every danger, convinced of her true destiny. With the might of Portugal humbled, the Court of the Sovereigns saw the rise of Torquemada, the establishment of the dreaded Inquisition, and the coming of Columbus, who left the woman he loved to make a dream reality. Ambitious and unfaithful, Ferdinand longed to lead his troops against the Moorish strongholds. Isabella knew a united Spain and a glorious future could be theirs, but they must only share it together.