The Erfurt University Library keeps the library of Johann Christian von Boineburg: ten thousand books, and in almost every one there are underlinings, marginalia, references to other books, tables of contents of planned works, even handwritten parts of such works in bound bundles of notes.

Boineburg, who was born on April 12, 1622, was the most important advisor to the Elector of Mainz after the Thirty Years' War and was one of the most important politicians in the empire until his fall in 1664, and one of the architects of the post-war order.

In his later years he was forced to act privately, became a mentor to the young Leibniz and campaigned for an Irish overcoming of the confessional divisions in Germany.

He also encouraged his learned friends

One of the tables of contents noted in the endpapers of the books is of particular interest.

"De usu errorum" was supposed to be the name of a work by Boineburg, which was never published and perhaps never completed.

The busy politician was a networker, a project planner, a book enthusiast, but not a patient draftsman of large folios.

So he was working on a book about errors.

How should one translate this "usus"?

Is it only for use or also for benefit?

Or should one try – anachronistically modern – the concept of role: the role of errors in political affairs?

Or even: the political function and functionalization of errors?

Then Boineburg's analyzes could become relevant over all the changes of four centuries.

The more corruption, the more lawyers

Let's try to get a picture of the content of the work from the fragmentary tables of contents.

Suddenly we embark on a scavenger hunt through the library, where the traces of reading in individual works always point to different parts of the library.

In 1646 - the peace negotiations in Münster and Osnabrück were in full swing - the twenty-four-year-old Boineburg bought Bogislaw von Chemnitz's pseudonymously published account of the structures of the Old Empire, Dissertatio de ratione status in Imperio nostro Romano-Germanico.

In the late autumn of 1647 he took up the book again.

Chemnitz complains that the empire has become "dissimilar to itself" because the old freedoms and self-determination have been superimposed by Roman law and curtailed by imperial power.

A whole caste of interpreters of the Justinian code appeared and made themselves comfortable in the administrations.

"Therefore," he writes, "as in a completely corrupt state, there are many laws and many lawyers.

As a result, there are countless disputes between private individuals, and there is a loss of credibility in the public sphere.” Boineburg crosses this out and notes in passing, as far as private law is concerned: “Compare Diodor Tulden's 'De causis corruptorum judiciorum eorumque remediis'”.