A letter,

written in 1547 by Emperor Charles V of Habsburg to his ambassador in Paris

and forgotten for centuries,

has been deciphered by four researchers.

To interpret the missive, which was

in the collections of the Stanislas library in Nancy

, it took

six months of work

and the contribution of the

Laboratoire lorrain de recherche en informatique (Loria) of Nancy,

associated with that of a

historian from the University of Picardy .

The decryption, five centuries later, of what

appeared to be "intelligible" symbols

now sheds new light on the relations between the

kingdom of France

, at the time led by Francis I, and

the Holy Roman Empire

.

Charles V of Habsburg, one of the greatest sovereigns in world history, ruled over such a vast territory that

"the sun never set" over his kingdom

.