French-style two-part work with a "thrilling" allegro, and all but five of the vocal numbers, are based on earlier works, though subject in many cases to significant adaptation and reworking. Examples of recycled material include Pallas's "Col raggio placido", which is based on Lucifer's aria from La resurrezione (1708), "O voi dell'Erebo", which was itself adapted from Reinhard Keiser's 1705 opera Octavia. Agrippina's aria "Non ho cor che per amarti" was taken, almost entirely unchanged, from "Se la morte non vorrà" in Handel's earlier dramatic cantata Qual ti reveggio, oh Dio (1707); Narcissus's "Spererò" is an adaptation of "Sai perchè" from another 1707 cantata, Clori, Tirsi e Fileno; and parts of Nero's aria in act 3, "Come nube che fugge dal vento", are borrowed Handel's oratorio Il trionfo del tempo (all from 1707). Later, some of Agrippina's music was used by Handel in his London operas Rinaldo (1711) and the 1732 version of Acis and Galatea, in each case with little or no change. The first music by Handel presented in London may have been Agrippina's "Non ho cor che", transposed into Alessandro Scarlatti's opera Pirro è Dimitrio which was performed in London on 6 December 1710. The Agrippina overture and other arias from the opera appeared in pasticcios performed in London between 1710 and 1714, with additional music provided by other composers. Echoes of "Ti vo' giusta" (one of the few arias composed specifically for Agrippina) can be found in the air "He was despised", from Handel's Messiah (1742). Two of the main male roles, Nero and Narcissus, were written for castrati, the "superstars of their day" in Italian opera. The opera was revised significantly before and possibly during its run. One example is the duet for Otho and Poppaea in act 3, "No, no, ch'io non apprezzo", replaced with two solo arias before the first performance. Another is Poppaea's aria "Ingannata", replaced during the run with another of extreme virtuosity, "Pur punir chi m'ha ingannata", either to emphasise Poppaea's new-found resolution at this juncture of the opera or, as is thought more likely, to flatter Scarabelli by giving her an additional opportunity to show off her vocal abilities. The instrumentation for Handel's score follows closely that of all his early operas: two recorders, two oboes, two trumpets, three violins, two cellos, viola, timpani, contrabassoon and harpsichord. By the standards of Handel's later London operas this scoring is light,