Trudelies LEONHARDT is of Dutch-Austrian parentage and comes from a family of musicians, her brother being the well-known harpsichordist Gustav Leonhardt.

She studied in Amsterdam with Johannes Röntgen, Anthon van der Horst and Nelly Wagenaar and was awarded the Soloist-diploma cum laude and the "Elisabeth Everts-prijs".

She also worked in Paris with Yves Nat and Marguerite Long.

Numerous orchestras have engaged Trudelies Leonhardt as soloist for their concerts, The Amsterdam Concertgehouw Orchestra, The Tonhalle Orchestra of Zurich and The London Mozart Players among them.

She has long been especially interested in the fortepianos of the late 18th and early 19th century and nowadays devotes her musical activity entirely to these.

Trudelies Leonhardt plays a Benignus Seidner grand piano, built un Vienna circa 1815 and restored in 1977. It is tuned to the concert pitch of 1815, 415 Hertz. She recorded several cds with this instrument.

With the construction in 1709 of his "gravecembalo col piano e forte" (literally "harpsichord with softness and loudness"), Bartolomeo Cristofori (1651-1731), court musician to the Medici in Florence, invented an instrument that, as the forerunner of the modern piano, was to be immensely successful. He had had the idea of replacing the jacks of the harpsichord, by which the strings are plucked, by little hammers. It was the expressive power of the "pantaléon", a larger form of the dulcimer, that had suggested this to Cristofori, the strings of this instrument also being struck with hammers. The fortepiano was born!

The new instrument opened up new expressive potential: the player could now achieve smooth dynamic transitions from piano to forte by using only the touch, just as on the clavichord, but with much greater power. The two Cristofori pianos that have been preserved are fined with an action on which the mechanics of our present-day instruments is based.

Surprisingly enough, however, the piano did not develop further in Italy, its birthplace, bur in Germany. And how rapidly it spread from there! By 1800 the piano had taken the place of clavichord, spinet and harpsichord all over Europe, becoming the house instrument par excellence of the bourgeois family. A wide variety of forms was produced: grands, square pianos, lyre-pianos, pyramid-pianos or giraffe-pianos.

But let's return to the year 1726, when Gottfried Silbermann (1683-1753) built the first German piano, based on Cristofori's action: the hammer is fixed to a bridge inde­pendent of the key; touching the key moves the hammer towards the string by means of a peg or trigger fastened diagonally to the key. Johannes Zumpe introduced this construction to England, where production of the new instrument met with great success. The square piano was initially the most popular form.

In 1771 Americus Backers added the escapement mechanism, where the trigger releases the hammer so that it automatically falls back into place even while the key is still depressed, and the so-called "English action" was invented. John Broadwood (1732-1812) and Robert Stodart also contributed to the development of the English action.

This system was subsequently used in France by Sebastian Erard (1752-1831) and Henri Pape (1789-1825). Great credit is due to Erard's firm for the extension of the English action in 1821 by the addition of a mechanism enabling double escapement: the hammer is propelled towards the string again while it is falling from the first blow This repetition mechanism made it possible to repeat the same note much more quickly: an important step!

What happened after Silbermann in Germany itself? One of Silbermann's pupils was the great Johann Andreas Stein from Augsburg (1728-1792), who transformed the traditional action of the instrument: in his piano, the hammer rests horizontally on the key, which, when struck, lifts the hammer by means of a fork at its edge. The part that holds back the end of the hammer is movable, thanks to a small spring, and thus allows the hammer to be released. Stein's invention was given the name "German or Viennese action".

The piano manufacturers who used this system included Andreas Streicher-Stein (1761-1833), Conrad Graf (1782-1851), Ignaz Bösendorfer (1794-1859), Carl Andreas Stein (1797-1863) and Friedrich Ehrbar (1827-1905).

Up to the end of the 19th century, in the course of which the majority of German piano-makers decided in favour of the English action combined with the double escapement, both of the mechanical actions influenced the style of piano compositions. The English action with its greater dynamic possibilities and a harder attack allowed a more striking, energetic and plastic interpretation (which made Beethoven, for one, prefer the English instruments), while the lighter Viennese system was better suited to more flowing, more brilliant and cantabile playing.

The development of the fortepiano in the 19th century went hand in hand with the intentions and techniques of the composers and with the expectations of their audiences. The search for a fullerbodied sound, the growing interest in music among a much wider public, the need for larger recital rooms -these wereall new demands that the relatively fragile instruments could no longer satisfy. New developments were unavoidable, and came in abundance.

A short list of dates gives a summary of the action used in each case (which tended subsequently to spread gradually throughout Europe), from the gravecembalo -still made entirely from wood, with its thin soundboard (ca. 4 mm), its range of four then five octaves, its fragile little hammers covered with leather and its fine strings under little tension ­to the modern grand piano -with a cast-iron frame, a soundboard up to 10 mm thick, a range of71/2 octaves, robust hammers covered with felt and ten times as thick as those of the gravicembalo, and reinforced strings placed under extreme tension.