Bartolomeo Cristofori's production of a cembalo with a viable hammer action, first documented in 1700, has always been recognized as an epochal breakthrough for Western music. Commencing an article discussing three grand pianos in the Florentine tradition, John Koster observed astutely that ‘arguably, no new invention in the history of music has had a greater or more lasting influence. Within a few decades of its appearance, Cristofori's invention, the piano, was known and imitated throughout most of Europe’ (see ‘Three Grand Pianos in the Florentine Tradition’, Revue française d'organologie et d'iconographie musicale 4/2 (1999), 95). Yet most people today have never seen or heard any such instrument. The Italian fortepiano in the first half of the eighteenth century has received a share of attention from scholars, but almost none of it has been connected with a direct experience of hearing or playing a viable example. The number of surviving originals is excruciatingly small, and in their current condition none of them, not even the cherished 1720 piano in the Metropolitan Museum, can convey an adequate impression of the sound and expression that this design is capable of realizing, all having experienced more or less alarming traumas during their lifespan of three centuries. One need only listen to Mieczysław Horszowski's classic recording of the Giustini sonatas, welcome though it is to have such aural documentation of a historic instrument, to recognize that nobody in eighteenth-century Italy would have been particularly excited about an instrument that, straining to speak a perfect fourth below any normal pitch, sounds more or less like a thumpy clavichord with a head cold. It plays louder and softer, indeed, but the tone is hardly beautiful, which does not at all accord with the contemporary report of Maffei (1711) regarding Cristofori's piano that ‘the ear … becomes so charmed that one never tires of it, and the common gravicembali no longer please’ (with appreciation, I quote, here and later, the translation of Maffei's article by Stewart Pollens, included in his book The Early Pianoforte (Cambridge: Cambridge University Press, 1995)).

Something does not add up. If the new gravicembalo col pian' e forte truly represented the breakthrough that Koster posits, it must have been effective in producing a longed-for musical experience, and the fact that these instruments continued to be produced for many decades confirms that they were considered highly desirable. The piano embodied musical resources that Italian musicians and listeners prized – naturalness of expression, singing tone and timbral charm, among others. If the solo keyboard music they composed during this era generates a tepid response from modern listeners and players, we must not be hearing it as they did.

Intrinsically – and I need not shrink from the assertion – the Florentine piano is a beautiful-sounding and expressively effective musical instrument. The response ‘wow!’ from those hearing it for the first time in person is not unknown. Being essentially an Italian harpsichord judiciously reinforced with a heavier stringing gauge and other adjustments to absorb the violence of the sound-producing event, it retains just enough of the bright high-overtone stack of its plucked progenitor to generate a tangy sizzle that imparts precise definition to the attack at all dynamic levels. When the instrument is heard from a slight distance, as Maffei recommends, the fundamental predominates, reinforced with great clarity when the two brass strings of a given pitch are in perfect intonation. Though the action is complex, the resonating structure of the instrument is balanced, easy to tune and just as stable as that of any other wooden-framed keyboard instrument (indeed, noticeably more so than many a classical Viennese fortepiano). Even more importantly, the shape of the sound envelope has the tremendous advantage of dying away quickly! Is it not one of the most evocative gestures in the baroque expressive palette to launch a tone and let it melt into the resonance of the sonorous body, and, by extension, the surrounding space? Whether from the voice, gamba or flute, this appears to be a near-universal response of performers to a natural impulse of expression. Among baroque keyboard instruments, however, the capacity to realize it is rare. The clavichord, in its delicate way, does it well, but it also possesses the Tragen der Töne (the ‘slurring of notes by a slur of dots’ described by Emanuel Bach); the harpsichord tone does indeed decay, but comparatively slowly (we should bury the canard that the pianoforte supplied a sustained tone lacking in the harpsichord, as quite the opposite is true); and the organ entirely lacks this capacity. Moreover, the pian' e forte has always claimed natural kinship with the most expressive instruments: Maffei praises its effect when ‘heard alone, like the lute, the harp, the six-stringed viol, and other most sweet instruments’. It is telling that some of the most ardent cognoscenti of the new keyboard instrument were famous castratos. Pollens reports the gift of a Cristofori piano from one castrato to another as early as 1703, and the great Farinelli possessed a piano made by Ferrini, Cristofori's pupil and successor, which Burney dates to 1730. Why would a renowned singer who could afford any keyboard instrument in existence bother to acquire such an unusual cembalo unless it offered decided advantages in support of vocal expression?

Over and beyond the intrinsic loveliness of the sound, the action of a fine Florentine replica is a joy to the touch. The key requires enough pressure from the finger to produce a secure and relaxed connection, creating a larger comfort zone for finger control than does the hair-trigger sensitivity of a well-regulated Viennese Prellmechanik, whose instant sensitivity is both a virtue and a challenge. Responsiveness is quick and flexible owing to the high mechanical advantage imparted to the hammer by the intermediate lever, a brilliant conception that forms the basis of piano actions to this day. It is true that the action posed a conundrum to many a contemporary player whose technique was based on precise timing of short, uniform finger movements unassisted by motion of the hand or wrist. To a player familiar with the feel and response of a modern piano action, however, the Cristofori action is recognizable as a very light version of a familiar environment.

To consider the nature of various keyboard instruments is essential in unravelling a puzzle regarding Italian keyboard repertoire in the middle third of the eighteenth century. Whether in one, two, three or more movements, the Italian keyboard sonata was spreading throughout Europe with far-reaching consequences for musical composition and performance. One might reasonably expect to find in so successful a repertoire the qualities that afforded such pleasure to listeners and players, yet nowadays this music commands passing attention, if any. One need only try out some of these pieces on the modern piano or harpsichord to discover that the results are not particularly delightful. A modern pianist may quickly tire of sequential patterning, predictable harmonic resources and repetitive, short phrase gestures. In addition, to impart any liveliness to the performance, she must struggle to project sufficient alacrity and focus through the curtain interposed by the modern piano's heavy action and slowly developing, slowly disappearing tone. The harpsichordist, meanwhile, in attempting to achieve appropriate balance of the ubiquitously active accompaniment figures (the Alberti bass being the locus classicus of these) inevitably confronts what has been called ‘the iron law of harpsichord dynamics’: the more notes, the louder. No matter how skilfully varied the harpsichordist's touch and rhetorically animated his delivery, there is often no way to render accompanied-melody passages in anything resembling a natural balance; the ear will inevitably attend to the activity of the supporting material. I hasten to acknowledge the many gifted artists among us who know how to overcome these challenges to often miraculous effect. All hail! But for the most part both modern pianist and harpsichordist will be just as happy to turn back to repertoire more congenial to the strengths of their respective instruments.

One may ask: what accounts for the passion of mid-century Italians to create a profuse repertoire of keyboard music that doesn't sound very satisfying and imposes a struggle upon the player? Thanks in part to the celebration of the three hundredth anniversary of the first documentary evidence of a Cristofori piano, an answer suggests itself. As modern instruments based on the Florentine school of pianoforte building are introduced more widely, we are able, for the first time, to examine this problematic repertoire in the light of a performance medium indigenous to it, the hammered cembalo.

Broadly speaking, eighteenth-century Italian music, whether liturgical, operatic or instrumental, emphasized expression, chiaroscuro and beautifully singing tone. In the hands of a suitably skilled player, according to Maffei, these are exactly the attributes of the pianoforte: ‘It requires a person … to regulate the strength of the varied pressure which should be given to the keys, and the graceful diminishing, at the [right] time and place, and to choose pieces suited to it, and delicate ones, and especially separating and making the parts progress, and to make heard the subjects in various places.’ This certainly covers a lot of ground! Significantly, Maffei situates the excellence of the instrument in its sensitivity (‘diminishing’, ‘delicate’) and a clarity that facilitates the voicing of parts in a way that serves both the older contrapuntal manner and the progressive cantabile style well.

The varied, nuanced dynamic inflection available on this pianoforte also imparts advantage to other common musical traits. Italian composers regularly turn to a quasi-tremolo alternation of a fixed pitch with others outlining a melodic gesture that may quickly dull the ear unless rhythmic inflection and grouping are applied. The most direct way to achieve this, readily available on the pianoforte, is to use dynamic nuance to suggest various directional impulses or shifts of character. Applied on the level of the short phrase, varied dynamics bring charm and interest to the literal repetitions of short passages, cadential or otherwise, that are frequently encountered in this music. Likewise, the repeated-note melodic figures for which Giovanni Platti betrays a particular fondness are much more easily and more pointedly shaped through dynamic inflection than they may be by the variation of note-lengths, timing and articulation, however artful, on the harpsichord. On the pianoforte, the very idioms that risk becoming tiresome if insufficiently nuanced may lend savour to even the simplest material.

The rise of the solo keyboard sonata in Italy had ramifications elsewhere in Europe. In northern Germany, by the mid-1730s, Gottfried Silbermann was adapting the Florentine action to his purposes, closely copying Ferrini's action, as the builder David Sutherland has shown (‘Silbermann, Bach, and the Florentine Piano’, Early Keyboard Journal 21 (2003), 45–63). In 1753 Emanuel Bach acknowledged the importance of this type of pianoforte in his treatise, saying (in William Mitchell's translation of the Versuch – Essay on the True Art of Playing Keyboard Instruments (New York: Norton, 1949), 36), ‘The more recent pianoforte, when it is sturdy and well built, has many fine qualities, although its touch must be carefully worked out, a task which is not without difficulties. It sounds well by itself and in small ensembles. Yet, I hold that a good clavichord, except for its weaker tone, shares equally in the attractiveness of the pianoforte.’ Clearly, Bach's allegiance to his beloved clavichord is under no threat from the pianoforte, but one might also cast his statement in the converse: that the fortepiano, with a stronger tone, shares equally in the attractiveness of the clavichord. It seems reasonable to conclude that the technical and expressive concerns Bach addresses so painstakingly in the eighteen progressive Probestücke that form part of his Versuch may be realized appropriately on the Florentine pianoforte (only excepting the Bebung encountered in two quasi-improvisatory passages). It was through the Florentine tradition that Bach had encountered pianoforte playing, and one may well wonder what instrument he had in mind by the time he started referring to the fortepiano by name in the Kenner und Liebhaber collections published between 1780 and 1787. It took Mozart until the 1780s to find the recently developed Austrian pianos completely satisfactory, and the notion that Bach in Hamburg would have been familiar with such instruments, let alone have composed his piano music with them in mind, certainly invites scepticism. It is not clear how quickly ideas about the Viennese fortepiano, designed along quite different principles from the Florentine tradition that had become well established in northern Germany by the 1760s, could have supplanted that branch of pianoforte culture. What kind of instrument was Bach calling a pianoforte?

Just as intriguing as Emanuel's connection with the Florentine pianoforte tradition are its implications for the work of others in his family and professional circles. Was not Johann Christian a student in Berlin and Italy before establishing his career in London as a leading devotee of the English pianoforte? Did not Wilhelm Friedemann Bach adopt the vogue for dynamic contrast in his polonaises, sonatas and fantasias? Does not Müthel's fantastical style migrate comfortably from its native habitat on the clavichord to the pianoforte? Was not Georg Benda in the service of the Prussian court before establishing himself in Gotha, and do not his sonatas and sonatinas partake of an aesthetic of sensibility and surprise similar to the manner of his former colleague Emanuel Bach?

Italian musical practice was also disseminated into Iberia and the Austrian Empire thanks to the widespread emigration of Italian composers and performers. Cristofori's connection with the Portuguese and Spanish courts through the agency of Scarlatti and Farinelli is firmly established, as is the rise of a refined Portuguese piano-building culture stemming from the Florentine school. Seldom considered, however, is the potential relevance of the pianoforte to the work of Austrian composers prior to around 1775. When I recently performed before members of the Society for Eighteenth-Century Music and the North American Haydn Society, I could not resist seizing the rare opportunity to share a live experience of the Florentine piano with an audience having foreknowledge of its identity and a predisposition to hear it with interest. Some time earlier I had noticed a certain congruence between an early sonata of Haydn and the instrument at hand. This pianoforte, built in 2005 by Sutherland, is based on Cristofori's design, as transmitted by his pupil Giovanni Ferrini in his only surviving piano action. Its compass, running four and a half octaves from G¹ to d³, matches precisely that required by Haydn's early, undated and unmistakably Italianate sonata in G major hXVI:6. The melody of the first movement is accompanied in ways that might have been lifted directly from one of Alberti's sonatas published in 1748, including a simple linear bass and Alberti-bass figures; the Adagio applies an unusually thick repeated-full-triad accompaniment to a florid and highly expressive cantilena, closely resembling in texture the Adagio of a Platti sonata published in 1742; and the finale deploys one Italian idiom after another with an unbridled brilliance more often associated with Scarlatti. Platti's publisher, Haffner of Nuremberg, also published collections of sonatas by various ‘celebrated Italian composers’ in 1756 and 1757. Whether or not Haydn had access to any of these particular volumes, he could scarcely have avoided encountering many a typical Italian keyboard sonata during his formative years in Vienna.

I cannot be sure that Haydn had the pianoforte in mind when writing this or other early keyboard pieces, but he was unmistakably writing in a style natural to it. When we consider that the middle third of the eighteenth century increasingly favours chiaroscuro, accompanied cantabile melody, the repetition of single notes, short expressive figures, short phrases and a cultivated taste for sensitivity and elegance; and when a new keyboard instrument exists that can realize these traits both naturally and attractively; and when that instrument is well appreciated as soon as it appears and is produced and disseminated across a wide swath of Europe over a period of decades; then it is reasonable to question the assumption that the Florentine pianoforte represented an insignificant instrumental cul-de-sac in the history of music. Regardless of the extent of the external documentation that has so far or may yet come to light, the music itself informs us that the first era of the piano had arrived.

In our age of historically informed performance, it strikes attuned listeners as axiomatic to look to instruments as a component of musicological research. Historically grounded performance practice has successfully reanimated the communicative power of virtually all repertoires by turning to historically relevant instruments. Yet attitudes to the contrary persist, even among musicians, and they can run deep. As recently as 1979, discussing the choice of performance instrument for the keyboard works of J. S. Bach in a video interview with Bruno Monsaingeon, Glenn Gould felt entitled to smirk comfortably, ‘as far as I know, there's no back-to-the-Pleyel movement for Chopin’. Only three decades later the Chopin bicentenary of 2010 gave occasion to review this claim. In the face of myriad revelatory performances on pianos of Chopin's era and the successful replication of new romantic-era Pleyel pianos in at least two European workshops, Gould's attitude has been unmasked as quaintly irrelevant. Today the Florentine hammered cembalo, with its tercentenary rapidly receding, is newly available to reanimate a repertoire and to augment our estimation of it. It offers the opportunity for a fresh assessment of mid-eighteenth-century keyboard music through the satisfying reunion of style and medium. Originally the delight of a privileged few, the pian' e forte stands ready to be released from the inner sanctum of the privileged elite and the obscurity of historical neglect.