LONDON -- Two Fra Angelico paintings missing since the Napoleonic wars of the 18th century were discovered hanging in the study of a retired manuscript librarian, and will be auctioned by the woman's heirs.

The librarian, Jean Preston, found the two Renaissance works while she lived in California in the 1960s and her father bought them for her for about $380. Five years ago, Preston became curious about the pictures and contacted her alma mater, Bristol University, to see if any of the art history professors would evaluate her art.

"I went to visit and was rather startled to discover she had a number of extremely interesting pieces," said Michael Liversidge, a former dean of the arts department.

The two golden saints were the most intriguing.

Liversidge learned that the two had been among a set of six small panels by Fra Angelico separated and scattered when Napoleon invaded Italy in the 1790s. The paintings of two unidentified saints were part of an altar group displayed at the artist's Florence convent, San Marco, from around 1438. The paintings were commissioned by the bankers Cosimo Medici and his brother, Lorenzo.

"She said 'Oh my! That is very interesting,'" Liversidge said. "I think she was extremely pleased that what they were had been found out."

Preston, a retired curator of manuscripts at Princeton University, died earlier this year at age 77. Her heirs plan to auction the works in a sale that may fetch $1.9 million.

"She knew everything there was to know about medieval literature, but not a lot about art," said the librarian's nephew, Mar¿tin Preston.

The pictures came to public knowledge when Guy Schwinge of the Duke's of Dorchester auction house appraised the former librarian's collection.

"To put it in a nutshell, we are dealing with two works of art painted by one of the 'greats,' intended for his own church and commissioned by one of the greatest art patrons in history," Schwinge said in a statement.

Martin Preston was unaware of Liversidge's identification. His aunt appreciated pictures from an artistic and historical interest, but never thought of their value, he said. She was a frugal woman who lived simply, Preston said.

Duke's auction house plans to sell the paintings in March. The last time Fra Angelico's work sold, in 1972, two pictures fetched $439,000, Schwinge said.

Fra Angelico was born Guido di Pietro about 1395 and died in 1455. His convent still has the largest painting of the set.

Pope John Paul II beatified him in 1984, the first step toward sainthood, and decreed him patron of artists.