Editing Muzio Clementi (section)

===Publishing and piano manufacturing===
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In 1798, Clementi took over the firm Longman and Broderip at 26 [[Cheapside]] (then the most prestigious shopping street in London), initially with James Longman, who left in 1801.<ref>{{cite web |url=http://www.squarepianos.com/longman.html |title=Longman & Broderip |author=Michael Cole |date=10 October 2013 |access-date=27 October 2013}}</ref> Clementi also had offices at 195 [[Tottenham Court Road]] from 1806. The publication line, "Clementi & Co, & Clementi, Cheapside" appears on a lithograph, "Music" by [[William Sharp (lithographer)|William Sharp]] after John Wood (1801–1870), circa 1830s.<ref>{{Cite web |title=print {{!}} British Museum |url=https://www.britishmuseum.org/collection/object/P_1874-0613-1308 |access-date=2023-11-11 |website=www.britishmuseum.org |language=en}}</ref>

Clementi also began manufacturing pianos, but on 20 March 1807, a fire destroyed the firm's warehouses in Rotten Road, resulting in a loss of about £40,000.<ref>{{Cite book |last1=Cranmer |first1=Margaret |url=https://www.oxfordmusiconline.com/grovemusic/view/10.1093/gmo/9781561592630.001.0001/omo-9781561592630-e-0000005937 |title=Clementi |last2=Jones |first2=Peter Ward |year=2001 |isbn=978-1-56159-263-0 |doi=10.1093/gmo/9781561592630.article.05937 |url-access=subscription}}</ref> That same year, Clementi made an agreement with [[Ludwig van Beethoven]] (one of his greatest admirers), which gave him full publishing rights to all of Beethoven's music in England. He [[copy editing|edited]] and interpreted Beethoven's music but has received criticism for editorial work such as making harmonic "corrections" to some of Beethoven's scores.

In 1810, Clementi stopped performing in order to devote his time to composition and to piano making. On 24 January 1813, together with a group of prominent professional musicians in England, he founded the "Philharmonic Society of London", which became the [[Royal Philharmonic Society]] in 1912. In 1813 Clementi was appointed a member of the [[Royal Swedish Academy of Music]].

Meanwhile, his piano business had flourished, affording him an increasingly elegant lifestyle. As an inventor and skilled mechanic, he made important improvements in the construction of the piano, some of which have become standard.