Tamerlano was the second of three Handel masterpieces which highlighted the middle years of the Royal Academy of Music. Giulio Cesare had been the smash hit of the 1723-1724 season at the King's Theatre in the Haymarket, and Tamerlano began the 1724-1725 opera season. Again, Cuzzoni and Senesino were the two principals, playing the lovers Asteria and Andronico. Asteria is a full-blooded female lead. A true heroine, loving daughter, and adoring lover of Andronico, she brings the opera to life. Andronico, although not as well-hewn a character as Asteria, is a good foil for her heroism and is supplied with plenty of beautiful music as a lover. The strongest character in the plot is Bajazet, whose pride antagonizes his arrogant adversary Tamerlane. Bajazet is the misused father of Asteria, and is cast as a tenor. Bajazet is the first great tenor role in the history of opera. Tenors were uncommon in eighteenth century opera, especially in heroic or prominent roles. So the new singer brought in from Italy, Francesco Borosini, was something of a novelty to the London public and immediately gained a following. The opera was very successful and played to full houses throughout its run.
As in Giulio Cesare, the libretto is by Nicola Haym. The opera seria conventions are written into the libretto by Haym in such a way as to allow room for dramatic manipulation on the part of Handel. When he wanted to create a more dramatic and flexible form out of the standard scenic repetitions of recitative and aria, he altered the structures of the arias. The second act of Tamerlano offers a perfect example. Instead of exit arias, three characters in a row are given aria settings that are not in the da capo form. Bajazet sings a cavatina, followed by a bar form aria for Andronico, and a repeated binary-form aria for Irene. Finally, the grand heroine receives a full blown da capo exit aria. The denial of convention must have been extremely startling to the audience, used to the regularity of form of the opera seria.
The orchestration of Tamerlano is again brilliant and imaginative, making use of an early type of clarinet known as the chalumeau. Handel and Rameau were the first to write for this instrument. The finale of the opera is an extended piece built up of recitatives, ariosos, and ensembles that build to the end. The climax of the opera is breathtaking, as the dying Bajazet sings to his heartbroken daughter, "Dearest daughter, weep no more." Tamerlano was finished with even more than Handel's characteristic speed; he composed the work in 20 days.