Made in the Imperial Porcelain Manufactory, the plate was from the Raphael service, an Imperial Russian dinner service from the reign of Nicolas II.
Marked and dated 1898 on the reverse, the 9 1/2in (24cm) diameter plate was in immaculate condition, having been kept in a case for 80 years in a house in Bangor.
With interest from Germany, USA, Russia, France and the UK, fierce bidding between an American on the phone and the London trade ensued.
The plate sold above its £10,000-12,000 estimate to the latter at £19,000 plus ten per cent buyer's premium.