Zachow was well acquainted with the Italian masters, and his own Church music shows a vivid dramatic sense; it is easy to see how much Handel learned from him. But although Church cantatas and organ music may have sufficed for the majority of the innumerable worthy German musicians of those days, the form of music which excited the curiosity and interest of the livelier spirits was certainly opera. By 1700, opera had established itself all over Italy, supported mainly by the great princes, but at Venice maintained on a commercial basis by the citizens themselves since 1637. The first attempt at a German opera was made by Heinrich Schütz, at Torgau, ten years earlier. Vienna introduced Italian opera in 1631, and, generally speaking, the Catholic princes of Germany, who one after another followed the example of Vienna, preferred opera in Italian. Protestant Germany inclined more to opera in its own language, though towards the end of the century Italian gradually gained the upper hand at the more important courts. Native German opera owed its origin partly to the visit of the English comedians early in the century, and partly to the musical plays acted by school-boys; from the English "jigs" came the use of short popular songs, and from the school plays the tendency of the early German operas to be of a more or less sacred or edifying character.
Handel's friend, the composer Telemann, tells us that it was not unusual for students from the University of Leipzig to go to Berlin to hear the Italian opera, which had been established by the Electress Sophia Charlotte in 1700, and this suggests that Handel's visit to Berlin may have taken place in 1703 rather than in his childhood. But he certainly had opportunities for seeing operas nearer home. There had been many German operas performed at Halle itself during the twenty years before Handel's birth, and Duke Johann Adolf opened an opera-house at Weissenfels in 1685, in which Philipp Krieger produced German operas regularly for the next thirty years. There was thus every reason for young Handel's growing ambitious to become a composer for the stage, although we have no evidence of his having ever attempted dramatic composition until he left Halle in 1703.
The most important of all the north German opera-houses was that of Hamburg, where the opera did not depend on the patronage of a court, but was organised, as at Venice, as a public entertainment. Hamburg had attempted German opera as early as 1648, and it is interesting to note that the English composer William Brade was one of those who provided the music; but the real history of the Hamburg opera may be said to begin with the performance of Theile's Adam and Eve in the newly built theatre in the Goose-Market in 1678. When Handel arrived in Hamburg in the summer of 1703 the biblical operas had long come to an end, and the theatre was under the management of Reinhold Keiser.
Keiser was a musician of remarkable genius. His father was a disreputable organist, and his mother a young lady of noble family who had been hastily married at the age of sixteen. Born near Weissenfels in 1674, he had begun his operatic career at Brunswick at the age of eighteen; three years later he took over the direction of the opera at Hamburg, where he produced a large number of operas composed by himself. As a composer, Keiser had a singular fluency of melody in a style that hovers between those of Germany and Italy; had he been a man of more solid character he might have accomplished greater things. But he had inherited from his parents a love of pleasure and debauchery; extravagant in his private life, he was no less extravagant in his theatrical management, and was ready to provide his audiences with anything in the way of startling sensation. One of his most famous operas was on the subject of Störtebeker, a notorious highwayman (1704), in which murders were represented with the most disgusting realism.
Hamburg was the Venice of the north and, like Venice, a city of pleasure; but its pleasures were often of a coarse and licentious description. Life in Hamburg was probably not much unlike that of Restoration London; but though Keiser may well be set beside Purcell, Hamburg had no dramatists to compare with Congreve, hardly even with Shadwell. Jeremy Collier, however, was far outdone in vituperation by the puritan clergy who, not altogether without reason, castigated the immorality of the Hamburg stage.
Handel seems to have arrived in Hamburg in early summer of 1703, for we first hear of him there on July 2, when he met Johann Mattheson in the church of St. Mary Magdalen. It seems to have been a chance acquaintance, to judge from Mattheson's account; it stuck in Mattheson's memory for many years and he remembered especially the pastry-cook's boy who blew the organ for Handel and himself. Mattheson was four years older than Handel; he was one of those precociously gifted, versatile, attractive, and rather vain young men who are endowed with so many talents that they never achieve distinction in any branch of art. He is remembered now only by the literary work of his later life, in which he shows himself as a voluminous pedant and an embittered critic. He made friends with Handel on the spot, and took him under his own protection, providing him with almost daily free meals at his father's house. He evidently regarded him as a very simple and provincial young musician, a notable organist indeed, and a master of such learned devices as counterpoint and fugue, but a dull composer, turning out endless arias and cantatas with no sense of the fashionable Italian taste.
It was Mattheson, by his own account, who introduced Handel to the musical life of Hamburg. The opera was closed for the summer, and Keiser's celebrated winter concerts, at which the wealthy society of Hamburg listened to the most famous singers and regaled themselves with tokay, had not yet begun; but there was no lack of social distractions, in which music no doubt played its part. In August the two friends made a journey to Lubeck, to compete for the post of organist at the Marienkirche in succession to Dietrich Buxtehude, who was nearly seventy and ready to retire. But both Buxtehude and the town council insisted that the new organist should marry his predecessor's daughter, in order to save the town the necessity of providing for her; she was considerably older than the two youthful candidates, and they both withdrew in haste. Late in life Mattheson married the daughter of an English clergyman; Handel remained a bachelor to the end of his days.
It was no doubt through Mattheson that Handel, in the autumn, entered the opera band as a humble second violinist. He seems to have been of a very retiring and quiet disposition, although of a dry humour. Opera management at Hamburg was no less precarious than it was in London; Keiser could not afford the Italian singers patronised by the German princes, and his performances had often to be helped out by amateurs of all classes. On one occasion the harpsichord-player failed him; Handel took his place at short notice, and his musicianship was at once recognised. Unfortunately Mattheson, whose chronology is always rather uncertain, does not tell us when this occurred. In addition to his duties in the orchestra, Handel earned a living by teaching private pupils, and through Mattheson he was engaged by Mr. John Wyche, the English Envoy, as music-master to his small son Cyril.
Early in 1704 Mattheson went to Holland, where he had some success in organising concerts at Amsterdam, and was offered the post of organist at Haarlem. He seems to have had some idea of seeking his fortune in England; he spoke English well, and may have had useful connexions in England through Mr. John Wyche. But in March Handel wrote to him that the Hamburg opera could not get on without him, and to Hamburg he returned. It soon must have become clear to him that Handel was rapidly outgrowing any need of his condescending patronage. A Passion according to St. John, the words of which had been written by Postel, an opera-poet turned pietist, had been set to music by Handel, and performed on Good Friday with marked success. Mattheson arrived too late to hear it, but it is significant that twenty years later he published a scathing criticism of it, although it is a work of little importance in relation to Handel's complete career, and can seldom have been performed. A Passion oratorio by Keiser was produced at the same time, it may well have been that Handel's work, youthful and conventional as it is, was enough to arouse the jealousy of both Keiser and Mattheson.
Shortly after Easter, Keiser began the composition of a new opera, Almira, on a libretto by the local poet Feustking, but for some reason or other he found it necessary to call in Handel's assistance, and eventually left the whole work to Handel to compose. It was to be produced in the autumn. Handel seems to have consulted Mattheson over every detail of the opera; there exists a complete score in Mattheson's handwriting, with corrections and additions by Handel. Mattheson spent the summer enjoying a country holiday in Mecklenburg; Handel probably went on with his opera, at Hamburg. In October, just as the opera season was reopening, Mattheson contrived to get himself engaged by Sir Cyril Wych as tutor to his son; he also took over the boy's musical education, hinting that Handel was dismissed for neglect of his duties. In view of Handel's strictly honourable character it is difficult to believe that he was guilty of neglect, and we may naturally suppose him to have resented the loss of a lucrative appointment.