The long careers of Carl Philipp Emanuel Bach and Joseph Haydn coincided with fundamental transformations in how keyboard instruments were built and played and how composers wrote for them. Haydn's keyboard music probably saw the more profound changes in compositional style, yet C. P. E. Bach and others preceded him in discovering ways to incorporate new keyboard idioms into pieces written for new types of instruments. Bach gradually shifted from writing generic keyboard music to composing in idioms most appropriate to two-manual harpsichords, unfretted clavichords or fortepianos. Haydn likewise began writing in a generic idiom; many works that have been posited as having been meant for the clavichord cannot in fact be assigned clearly to that or any other specific instrument. Although Haydn did eventually turn to writing specifically for the fortepiano, he too made a gradual, and relatively late, transition from a generic approach to one that centred on the grand fortepianos of the late eighteenth century. Bach's influence on Haydn is inseparable from the matter of the keyboard instruments. Although the precise nature and extent of Bach's influence cannot be determined, compositional elements derived by Haydn from Bach's music range from superficial thematic and notational parallelisms to fundamental conceptions of what keyboard music could be or could express.

The most historically significant and widely influential pianoforte designs, both for use in public concerts and for domestic music making, first appeared in the later 1760s, mostly as the work of immigrant German-born craftsmen working in London. But their work was preceded by a handful of pioneering instrument makers whose lives have been largely unreported until now. In this paper the authors report on the life and work of three such immigrant craftsmen who made pianofortes and related instruments in London in the period 1740–65. Two of them, Roger Plenius and Herman Viator, met with great personal misfortunes, while the other, Frederick Neubauer, crowned his career with a great triumph which has never been widely reported, though unhappily not one of his instruments is known to survive. The authors' findings are drawn from newly located contemporary newspaper notices and original manuscripts held at The National Archives, Kew and the Bancroft Library, London.

Joseph Merlin (1735–1803), ‘Ingenious Mechanick’, musical-instrument maker and flamboyant showman, is perhaps best remembered for his Museum in Princes Street, London, with its scintillating displays of automata and extraordinary inventions. Two newly identified sets of Court documents, Nicholl v. Merlin, 1779 and Merlin v. Celsson, 1779–81, now provide insights into previously unknown aspects of his business dealings and personal life. The former concerns a dispute over a house that Merlin commissioned to be built in 1776, the latter a violation of his 1774 combined harpsichord-pianoforte patent rights. Material relating to Lavigne Verel, his musical instrument foreman from 1773 to 1781, is also reported. Amongst other novel findings, perhaps the most surprising is Merlin's marriage in 1783. Contemporary primary-source material consulted includes original manuscripts held at The National Archives, UK, the Scone Palace Archives, Parish Registers, Land Tax and Apprenticeship records and numerous contemporary newspaper advertisements and notices.