He arrived in London in 1845 and made various appearances as a pianist. In November of that year, his opera "Maritana" was performed at Drury Lane with great success, and was later presented internationally, including Dublin (1846), Vienna, Austria (1848), and in Australia. Wallace's sister, Elisabeth, appeared at Covent Garden in the title role in 1848. "Maritana" was followed by "Matilda of Hungary" (1847), "Lurline" (1847/60), "The Amber Witch" (1861), "Love's Triumph" (1862) and "The Desert Flower" (1863) (based on the libretto of Halévy's "Jaguarita l'Indienne").