Marie Antoinette wrote these or more expressions of affection to Axel von Fersen, a close friend and rumored lover. — to Axel von Fersen, her close friend and rumored lover. Later, someone used dark ink to write over the words to dampen the exuberant, possibly amorous language.

French scientists devised a new way to find the original writing by separating the chemical compositions of the inks used in historical documents. The French scientists tested their method by analysing the private letters that were exchanged between the French queen, and the Swedish count. These letters are kept in the French national archive.

This allowed them to read the original words, and even identify the person who had scratched them out — Fersen.

“It’s always thrilling when you discover that your past can be more interesting than you thought,” Rebecca L. Spang, historian at Indiana University who studies the French Revolution, said. She was not part of the study.

These letters were exchanged between June 1791 to August 1792, a time when the French royal family had been trying to flee France and was under constant surveillance in Paris. Soon, the French monarchy was abolished and Marie Antoinette, along with her husband Louis XVI would be executed.

“People used a lot more flowery language in this period — but it’s very strong and intimate here. “We know that this text is a love relationship,” Anne Michelin, a material analyst from the Sorbonne’s Research Center for Conservation, and co-author on the research published in the journal Science Advances.

These letters are written on thick cotton paper and cover a wide range of topics, including political events and personal feelings. Redacted phrases such as “beloved” and “madly”, don’t alter the overall meaning of the letter, but they do change the tone of the relationship between sender and recipient.

Marie Antoinette met Fersen in France at the age of 18. They remained in touch until Fersen’s death.

“In 18th-century western Europe, there was a kind of faith in the letter as a writing medium that allows you to see the character of an individual like no other,” Deidre Lynch, a Harvard historian who studied the period’s literary culture, said.

She said, “Like a metaphorical condition of undress they’ve let down their hair and shown who they really were.”

However, savvy writers knew that letters could be read by multiple people. Invisible ink was a secret code used by some 18th-century European correspondents to conceal their true meaning from certain eyes.