In Donizetti's 1826 Gabriela di Vergy, derived from a French play of the same name, the eponymous French heroine, thinking her lover Raoul has died in the Crusades, has married Fayel, Count of Vergy. An unknown knight comes to their castle and is of course Raoul, who while away at war saved the life of King Filippo II of France (notice operatic warriors always do larger-than-life deeds, rather in the way anyone who discovers she had a previous life inevitably turns out to have been Cleopatra...but I digress). The king wishes Raoul to marry Fayel's sister and the knight's reluctance to do so angers Fayel, who later finds Raoul alone with his wife and suspects the worst. Fayel challenges Raoul to a duel and imprisons Gabriela. The opera concludes with a shocking scene: Gabriela's husband visits her in her dungeon and presents her with an urn containing the still-warm heart of the slain Raoul, and she dies of horror. [Curiously, the young Donizetti seems to have created this opera as an exercise in composing a tragedy rather than a work for performance; he later reworked much of the score into his 1841 Adelia.]
Just three years after Donizetti tackled Gabriela, Bellini tried his hand at a Crusades opera, based upon Voltaire's Zaïre. Zaira is set in a palace in Jerusalem, where a beautiful Christian captive, Zaira, is supposed to marry Orosmane, the sultan. In an interesting turn of plot, she happens to genuinely love him instead of its being a forced arrangement. However, the wedding is opposed by his vizier, Corasmino, who spreads word that the bride, who has delayed the ceremony by refusing to give up her faith, is really stalling because she is in love with a French knight, Nerestano. The previous year, Nerestano had left Jerusalem promising to return to free Zaira as well as ten POW knights; now he is back and has upped his demand to 100 men and the girl. Orosmane counters: he'll give up 99 men, but Zaira and the elderly prince Lusignano (historically, from 1194-1489, Cyprus was ruled by royal Crusaders descended from Gary of Lusignan, King of Jerusalem) must stay behind. The captive knights refuse to leave without Lusignano, and it turns out that he is none other than Zaira's father...and Nerestano's long-lost father, too! The opera ends sadly as Lusignano dies; Orosmane, coming upon his fiancée in the company of her "new" brother, misreads the relationship as his vizier had done, and fatally stabs her in jealousy; and the sultan then tabs himself when he learns she was faithful after all. [As with the Donizetti opera, this work -- a failure in its time -- underwent recycling: music from Zaida resurfaced in Bellini's I Capuleti e I Montecchi.]