Image caption The letters were sent from France to Warsaw via Berlin in envelopes like this one

Six letters written by Frederic Chopin, thought to be lost in 1939, have been found and donated to a Warsaw museum dedicated to the Polish composer.

The letters, written by Chopin to his parents and sisters between 1845 and 1848, were believed lost after the outbreak of World War II.

After it emerged in 2003 that they still existed in a private collection, moves were made to secure them.

Chopin was born in Poland in 1810 but spent half of his life in France.

According to museum curator Alicja Knast, the letters were last displayed in public in Poland in 1932 and were still confirmed as being in Warsaw in 1939.

It is thought the letters went missing, like many other cultural artefacts, after the Nazis invaded Poland.

The museum was assisted in their recovery by Marek Keller, a Polish art dealer now based in Mexico.

He acquired them directly from their owners, who Knast said wished to remain anonymous.

In the letters, written in Polish, Chopin describes daily life and his cello sonata in G minor, one of his few non-piano works.

The collection, which includes letters from Chopin's pupil Jane Stirling to his sister Ludwika, will be on display at the museum until 25 April.

Some of Chopin's letters were written in Nohant in central France, birthplace of his lover Amantine Dupin - aka writer George Sand.

Later this year Jeremy Irons and Sharon Stone will take part in a theatrical evening devoted to their romance at the Tuscan Sun Festival in Cortona, Italy.