Leanders own family was heavily influenced by Arianism, but he himself grew up to be a fervent Christian. He entered a monastery as a young man and spent three years in prayer and study. At the end of that tranquil period he was made a bishop. For the rest of his life he worked strenuously to fight against heresy. The death of the anti-Christian king in 586 helped Leanders cause. He and the new king worked hand in hand to restore orthodoxy and a renewed sense of morality. Leander succeeded in persuading many Arian bishops to change their loyalties.
Leander died around 600. In Spain he is honored as a Doctor of the Church.