Nathan undertook a runaway marriage with a music pupil, and another after his first wife's early death. Both spouses were Christian; however for both, Nathan also undertook and arranged synagogue marriages after the church ceremony. His hot temper probably accounts for a duel he fought over the honour of Lady Caroline Lamb, and his assault on an Irish nobleman who he thought had impugned one of his female pupils. The latter saw Nathan prosecuted, although he was acquitted. Nathan felt a special attachment for Lady Caroline; she was godmother to one of his children and he wrote her an appreciative poem in Hebrew, which he reprints in his "Recollections of Lord Byron".