While based at the Hague between 1725 and 1740, Unico Wilhelm wrote the six
Concerti Armonici. The
Concerti armonici, published anonymously in 1740, were printed in London in 1755 as compositions by the violinist and
impresario Carlo Ricciotti (c. 1681–1756). It has since been established that these were the work of Unico Wilhelm. There is no evidence that Ricciotti wrote any music. The concerti were dedicated to Wilhelm's friend, Count
Willem Bentinck. The slow movements of the concerti have expressive beauty. The Polish composer
Franciszek Lessel (1780–1838) asserted incorrectly that the
concertos were written by Pergolesi. Since the style of the
concertos is Italian, laid out in typical Roman fashion with four parts for violin and consisting of four parts instead of the Venetian three, they are comparable to works by
Pietro Locatelli. However, in 1979–1980 a manuscript of the six
concerti was found in the archives of
Twickel Castle (the castle where Van Wassenaer was born) labeled "Concerti Armonici." Although the handwriting was not by Van Wassenaer, the manuscript did have an introduction in his hand, reading: "Partition de mes concerts gravez par le Sr. Ricciotti". Because of the research done by the Dutch musicologist
Albert Dunning, there can be no doubt that the
concerti were, in fact, written by Van Wassenaer. Dunning quotes the composer's Foreword in full-- "Score of my concertos, engraved by Signor Ricciotti. These concertos were composed at different times between 1725 and 1740. When they were ready, I took them along to the musical gathering organized in The Hague by Mr Bentinck, myself and some foreign gentlemen. Ricciotti played the first violin. Afterwards I allowed him to make a copy of the concertos. When all six were ready, he asked permission to have them engraved. Upon my refusal he enlisted the aid of Mr Bentinck, to whose strong representations I finally acquiesced, on condition that my name did not appear anywhere on the copy and that he put his name to it, as he did. Mr Bentinck wanted to dedicate them to me; I refused absolutely, after which he told Ricciotti to dedicate them to him. In this way these concertos were published against my wishes. Some of them are tolerable, some middling, others wretched. Had they not been published, I would perhaps have corrected the mistakes in them, but other business has left me no leisure to amuse myself with them, and I would have caused their editor offence."
Concerto Armonico No. 2 in B flat Major (Allegro moderato) was among the works that formed the basis for
Igor Stravinsky's
Pulcinella, Tarantella, based on works considered at the time to be by
Giovanni Battista Pergolesi. Apart from
Concerti Armonici, three sonatas for recorder and continuo were also discovered in a Rostock archive by Wim Brabants in the early 1990s. ==References==