The Enchiridion of Pope Leo

In L'avocat's dictionary Referring to the Dictionnaire historique-portatif by Jean-Baptiste L'Avocat (1709–1765), a ubiquitous biographical and bibliographical reference in the 18th century.,
it is stated that this book is
supposed to be by Pope Leo III
And that the most
esteemed editions are those of 1525
and 1584.

It is this pope who
crowned Charlemagne Pope Leo III crowned Charlemagne as Emperor of the Romans on Christmas Day, 800 AD. This historical connection was often used to lend authority to the "Enchiridion," a book of prayers and charms supposedly gifted by the Pope to the Emperor.