George Frideric Handel's operas comprise 42 musical dramas that were written between 1705 and 1741 in various genres. He began composing operas in Germany and then for a brief time in Italy to modest success. It was not until he moved to England that he found great success in the genre. His first opera in England, Rinaldo (1711), was met with enthusiasm, and several more Italian operas soon followed. However, Handel's place as the central figure of opera in England during the eighteenth century was not solidified until, under the influence of Thomas Arne, he began composing large-scale works with English language texts. Though almost all his English language works are technically oratorios and not operas, several of them, such as Semele (1743), have become an important part of the opera repertoire. Handel's first opera (opera seria - serious Italian opera) was Almira (1705).
Handel's earlier operas tended to be of a lighter nature, although there are intermittent moments, such as the prison scene from Almira (1705), which are highly dramatic. Handel's music for his first operas in England was often derived from musical ideas and idioms found in his cantatas and other works written during his time spent in Italy (1706–09). For example, the characteristic harmonic structure of Agrippina (1709) is obviously a retention of material from this Italian period. In general, the orchestrations of Handel's earlier operas tended to be richer and smoother than in his later works, utilizing additional instruments like bassoons to achieve different tone colours. The music for Rinaldo (1711) notably used four trumpets, an instrumental choice that Handel never repeated elsewhere.
Beginning with Ottone (1722), Handel composed numerous operas for the Royal Academy of Music during the 1720s. With the exception of Flavio (1723), the operas from this period are more serious in tone and the musical expression is more astutely aligned to the opera's drama than in his earlier operas. Of particular importance from this period is Giulio Cesare (1724), which contains one of Handel's most expansive and emotively powerful scores. The sumptuous music and deft characterizations found in this work has made it one of the more frequently revived Handel operas during the 20th and 21st centuries. Also of note are Tamerlano (1724) and Rodelinda (1725) which have particularly striking leading tenor roles that Handel wrote specifically for Francesco Borosini. The later operas that Handel wrote for the Academy were not as successful as his earlier ones. The two major sopranos at the Academy, Francesca Cuzzoni and Faustina Bordoni, were intensely competitive, and Handel had to cater to them both equally in these latter Academy operas. With the exception of Admeto (1727), the attempt at balancing two leading soprano roles within an individual opera proved to hinder the work both musically and dramatically.