Вот что пишут о композиторе в словаре Грова:
Vančura [Wanžura, Wanczura, Wanskura], Arnošt [Ernest]
(b Vamberg [now Vamberk], Bohemia, c1750; d St Petersburg, Jan 1802). Russian composer and musical entrepreneur of Czech birth. After a short career as a lieutenant in the Austrian army, he arrived in Russia in 1783, passed himself off as a noble dilettante and took part in the reorganization of the St Petersburg theatres. After resettling in Moscow, he attempted to found a theatre of his own, but was out-manoeuvred by Michael Maddox, the established Moscow impresario, and spent a couple of years instead directing the music school attached to Maddox's Petrovsky Theatre. By February 1786 Vančura was back in St Petersburg, where he served until 1796 as a lavishly remunerated official in the directorate of the Court (later Imperial) Theatres, also appearing as ‘court forte-pianist’ in a quartet with violin, cello and harp (he also specialized in imitating animal cries and human bodily functions at the keyboard). After the failure of Fomin’s setting of Catherine II's second opera libretto, Noogorodskiy bogatïr' Boyeslavich (‘Boyeslavich, Champion of Novgorod’), the fast-talking newcomer was entrusted with her third, written in collaboration with her literary secretary, Alexander Khrapovitsky: Khrabroy i smeloy vityaz' Akhrideich (‘The Brave and Bold Knight Akhrideich’), a comic opera in five acts, also known as Ivan-Tsarevich. ‘Baron Vančura’s’ pastiche of folktunes was successful and remained in the repertory until 1810.
As an official of the Imperial Theatres, Vančura may have had a hand in revising the music of the popular folktune-based comic opera The Miller for its St Petersburg performances. This would help explain how the first movement of Vančura’s ‘Russian’ Symphony (Rossiyskaya simfoniya, subtitled ‘Sinfonie russe, composée d’airs ukraïniens’) became attached to The Miller as an overture; in the original vocal score (Moscow, 1884), the whole opera is misattributed to Fomin.