The expression here leads evidently to a wrong sense. The adverb at least, ought not to be connected with the substantive books, but with collector, thus:
Sixtus the Fourth was a great collector at least, of books.
Speaking of Lewis XIV.
If he was not the greatest king, he was the best actor of majesty at least, that ever filled a throne.
Ibid. letter 7.
Better thus:
If he was not the greatest king, he was at least the best actor of majesty, &c.
This arrangement removes the wrong sense occasioned by the juxtaposition of majesty and at least.
The following examples are of the wrong arrangement of members.
I have confined myself to those methods for the advancement of piety, which are in the power of a prince limited like ours by a strict execution of the laws.