Found in an attic, this portrait attracted enormous interest from Americans in a Dennis sale of April 3 and was sold at $90,000 (£49,725) to Stephen Score Antiques of Boston.

Enjoy unlimited access: just £1 for 12 weeks

Subscribe now

Initially no one took too much notice of the picture but, just because he liked the look of it, Frank Dennis decided to advertise it along with other pieces of more instantly recognisable potential. Things then started to look up for this folk art pastel portrait measuring 23 x 19in (58 x 48cm).

There was no authentication, but there was a suggestion that the portrait might be the work of an itinerant portrait painter from New Brunswick (NJ) by the name of Micah Williams, who was working c.1790-1830, and a date of around 1820 was mooted.

Now, this three-generation family business is proud to maintain that old fashioned auction process by which all items are held up in front of assembled bidders. No videos are used and, though the firm does run to a website, they do not go in for Internet bidding.

Telephone bidding, they are only too aware, can slow down an auction, but they do embrace that option and, while on this occasion they did have 11 lines in use - several of them being used by British or other European dealers in some sections of the sale - they did have to turn down telephone bids on this lot because all lines had been booked by dealers from the home state, and from New York, Pennsylvania, Chicago and various parts of New England.

Much of the higher bidding was indeed done over the telephone, but in the end it was Boston dealer Stephen Score, who had left nothing to chance and turned up in person, who made the winning bid of $90,000 (£49,275) from the floor. Score had expected to pay around $70,000 for the picture, but admitted, "I buy as a collector; I was passionate about it when I bought it and whoever buys it from me will also be passionate about it."

Other highlights in this best ever sale included two pieces of sculpture. A 4ft (1.15m) high bronze figure of Pan in Myth by the French expressionist painter, sculptor and teacher Antoine Bourdelle (1861-1929) was sold for $60,000 (£33,150) and a life-size wooden sculpture of the dancer and choreographer Martha Graham, made in 1977 by Venezuelan-American sculptor, Marisol Escobar, was bid to $39,000 (£21,545).