Apparently Tsar Alexander II was a bit of a ladies man. At the age of 47 he embarked on a passionate affair with the 18 year old Katia, an affair that was to last 14 years.

Throughout their affiar, Katia and Alexander wrote epic erotic letters to each other - sometimes several in a single day. And now they are available for the world to read, thanks to an auction in Paris.

Alexander II and Katia frequently embarked on what they referred to as “bingerle” - an activity that led Katia to bear the Tsar four children.

The letters were in French. But some sexual references were jotted down in Russian.

In 1871 Katia writes: “I saw in your eyes that you wanted to throw yourself at me to forget everything and enjoy our bingerle.”

In another 28-page missive she reminds the Tsar that she is pregnant and urges him: “not to dare have any bad ideas and to remain untainted … for I know you are capable in one moment when you want to make it (bingerle), to forget that you desire only me, and to go and make it (bingerle) with another woman.”