8 August 1584 (from London): “Pertinacem meum quanti faciam, scripsi, opinor, Litteris superioribus. Certè amantissimi mei nec prece nec pretio. Tibi tamen per Demetrium nostrum misi senem illum, ceteris quidem felicem, solo imperio, non sua, sed sicariorum scelere, infelicem. Conditionis oblitus videtur Demetrius. Nam hunc unum multò pluris Facio, quam Balbinum, Florianum, Numerianum. Sed Ortelio meo Pertinacem longè postpone. Agam igitur amoris officio, potius quam pretio aut permutatione. Si (quae certè mea fuit conditio) Numeriano tuo addas Balbinum et Florianum, Pertinax meus tuus esto. Balbinum si non potes, alium dato ex thesauro tuo, unde non est difficile conditionibus istis cumulate satisfacere. Interim donec utrinque placeant conditiones Pertinacem amato plurimum, et serva diligenter; et me, qui te facio maximi et magnopere velim ut tibi viro praestantissimo opera mea usui esse possit ; idque persuasum habeas rogo” (Den Haag, Koninklijke Bibliotheek, MS 79 C 4 (080), f° 41 ; Hessels 1887, no. 140, p. 322).
['I wrote, I think, in my last letter how much I value my Pertinax. Indeed my dearest friends would never get it, by prayer or by payment. But it was to you I sent, via our Demetrius, the old man, happy in every other respect, but unhappy with his sole reign which was not his fault but the crime of murderers.
Demetrius seems to have forgotten about my proposition. I value this one alone at much more than a Balbinus, a Florian or a Numerian. But I put Pertinax long behind my Ortelius. So I am doing this as a courtesy of affection, rather than for money or as a business exchange. If (which was indeed my proposal) you would add to your Numerian a Balbinus and a Florian, then my Pertinax is yours. If you can’t do the Balbinus, give another one from your collection, from which it isn’t difficult to fully accommodate my proposition. In the meantime until our business is mutually agreed, love the Pertinax a lot, and look after it carefully.' (translation from Burnett 2020b, p. 141)]