Keyboard range

The compasses of the instruments increased over the centuries. Keyboard music took the keyboard ranges available in its time into account.

B – a² (Halberstadt cathedral organ 1356 upper manual)	recorded by Praetorius 1619
B - a² (all keyboard)	common in 15. Jhd.
FGA – g²	German Clavicytherium late 15th c.
C/E – c³	very common until end of 17th c. with "short octave" in the bass. The spelling „C/E“ is related to the ton C sounding when the apparent key for „E“ is pressed. German Clavichords and Italian small harpsichords until 18th c.
C/E – f³	typical for Italian instruments of the 16th and 17th c.
C/E – c³ „split“ short octave	The apparent „F#" and „G#“ keys were split in two, sounding D and E (front) and F# and G# (back) German keyboard c1690, in Italy already c1650
C – c³ „long“ bass octave	England already 17th c.; German French and Italian instruments c1700 to 1770; typical for organ manuals to the 19th c.

During the 18th c, the four octaves compass was enlarged in many small steps to five octaves, with many variants even in the same workshop. (Gräbner in Dresden for instance made instruments with the compasses D’ – d³ as well as E’ – e³).

F’ – f³	common from first half of 18th c. to c1790
G’ – g³	Spanish harpsichords (?); English spinets
C – f³	organ manual till present: clavichords for rehearsing
F’/C – f³	Viennese „multiple split“ short octave; the apparent D-key divided in three sounding (front to back) G’, A’ and B' flat, the E-key divided in C and B' natural, and a common split octave D/F# and E/G#

Mozart composed for the range F’ – f³all his life, as did Haydn (with only one exception), Beethoven to 1803. But in Beethoven's lifetime and later to c1860 this development processed rather fast.

F’ – g³	some clavichords since the 1780s; some grands between 1795 and 1803
F’ – c⁴	clavichords since 1800, grands after 1803 to c1810; Haydn's loaned grand in London, Beethoven's Erard grand (his compositions from op. 53 „Waldsteinsonate“ to op. 81a have this range)
C’ – f³	some harpsichords by Shudi & Broadwood
C’ – c⁴	English grands between 1808 and 1820; Beethoven's Broadwood grand
F’ – f⁴	late clavichords after c1810, south German grands to c1840; (Beethoven's compositions from op. 81a,1809 to op.101)
C’ – f⁴	grands c1816 to 1840; Beethoven's Graf grand (his compositions from op. 101, 1816)
C’ – g⁴	grands c1840 Schumann's Graf grand
C’ – a⁴	grands c1840
A“ – a⁴	grands from c1850 to late 20th c.
A“ – c⁵	modern, frequent since c1970s

Squares and uprights often had a slightly reduced compass compared to grands. After the spread of the pianino upright as the sole piano for domestic use its compass was assimilated to the grand's.