is to his Tzarskoy Majesty (which farr be it from my thoughts) if I appropriate Serenissimus to my Master and Illustrissimus to Him than which nihil dici potest Illustrius.  But because this was in the time of the purity of the Latin tongue, when the word Serenus was never used in the Title of any Prince or Person, I shall go on to deale with the utmost candor, forasmuch as in this Nation the nicety of that most eloquent language is not so perfectly understood, which gives occasion to these mistakes.  I confess therefore that indeed in the declination of the Latin tongue, and when there scarce could be found out words enough to supply the modern ambition of Titles, Serenissimus as several other words hath grown in fashion for a compellation of lesser as well as greater Princes, and yet befits both the one and the other.  So there is Serenissima Respublica Veneta, Serenitates Electoriae, Serenitates Regiae, even as the word Highness or Celsitudo befits a Duke, a Prince, a King, or an Emperour, adjoyning to it the respective quality, and so the word Illustris.  But suppose it were by modern use (which I deny) depressed from the undoubted superiority that it had of Serenus in the purest antiquity, yet being added in the transcendent degree to the word Emperour, the highest denomination that a Prince is capable of, it becomes of the same value.  So that to interpret Illustrissimus unto diminution is to find a positive in a superlative, and in the most orient light to seek for darkness.  And I would, seeing the near Boyars and Counsellors of his Tzarskoy Majesty are pleased to mention the Title given to his Tzarskoy Majesty by his Cesarian Majesty, gladly be satisfied by them, whether ever any Cesarian Majesty writ formerly hither in High-Dutch, and whether then they styled his Tzarskoy Majesty Durchluchtigste which is the same with Illustrissimus, and which I believe the Caesar hath kept for Himself.  But to cut short, his Royal Majesty hath used the word to his Tzarskoy Majesty in his Letter, not out of imitation of others, although even in the Dutch Letter to his Tzarskoy Majesty of 16 June 1663, I finde Durchlauchtigste the same (as I said) with Illustrissimus, but out of the constant use of his own Court, further joyning before it Most High, Most Potent, and adding after it Great Lord Emperour, which is an higher Title than any Prince in the World gives his Tzarskoy Majesty, and as high a Title of honour as can be given to any thing under the Divinity.  For the King my Master who possesses as considerable Dominions, and by as high and self-dependent a right as any Prince in the Universe, yet contenting Himself with the easiest Titles, and satisfying Himself in the essence of things, doth most willingly give to other Princes the Titles which are appropriated to them, but to the Tzarskoy Majesties of Russia his Royal Ancestors, and to his present Tzarskoy Majesty his Royal Majesty