_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 t