Two 19th Century paintings thought to be of the romantic city of Venice, are actually views of the more rugged British naval port of Portsmouth.
Renamed: Procession of Boats with Distant Smoke, Venice (1845)
The landscape paintings by British artist JMW Turner were wrongly named for more than three decades.
Officials at Tate Britain uncovered the
bungle while researching a new show.
Ian Warrell, curator of the "Turner And Venice" exhibition said the works were wrongly named when they were shown at the Museum Of Modern Art in New York.
"The size of the canvas is substantially larger than that used for the 19 small Venetian pictures that Turner exhibited between 1840 and 1846," he said.
"Looking closely at the pictures it is apparent that there is no architectural element, as if the eye scans a seaward horizon from the shore.
"Nevertheless, the presence of so many festive crowds indicates that the quayside is not far away.
"Indeed, in one of them a line of soldiers in red uniform stands patiently to attention, while in the boats below people point eagerly toward the distant smoke.
"These English troops are clearly an anomaly in a Venetian subject, but would not be so in one closer to home."
He said the pictures could be of the arrival of the French king, Louis-Philippe, at Portsmouth on 8 October 1844, which Turner attended.
One of the works, formerly listed as "Festive Lagoon
Scene, Venice (1840-5)" has been renamed "The Arrival of
Louis-Philippe at Portsmouth 8 October 1844".
The other, "Procession of Boats with Distant Smoke, Venice (1845)" is now re-titled "The Disembarkation of Louis-Philippe at Portsmouth, 8 October 1844".
Turner and Venice is the first major exhibition devoted to Turner's trips to Venice and opens on 9 October at Tate Britain in London.
It will bring together more than 50 oil paintings and in excess of a hundred watercolours, as well as prints, maps and sketchbooks - as well as the two previously mistitled works.
The exhibition is set out like a tour of Venice.
Pictures courtesy of Tate Britain