He then went to Italy, and spent some time in Rome, where he had lessons with Raphael Mengs.
At Venice Brompton painted a conversation-piece, in which he introduced the portraits of the Duke of York and several English gentlemen then on their travels.
The picture was afterwards exhibited at the rooms in Spring Gardens in 1763, at which time he returned to England, and for some years practised portrait painting.
[1] Extravagant living and debtors brought him to the King's Bench, but he was rescued by the Empress of Russia, at whose request he went to St. Petersburg, where he was appointed portrait painter to the empress, and where he met with much employment.
During this time he was patronized by the empress favorite, Grigory Potemkin.