IV. John de Groot, brother to Cornelius and second son of Hugh, studied
under the famous Justus Lipsius, who esteemed him much: in some letters
of that learned man to John de Groot he speaks of him with great
commendation. There is one, written in 1582, in which Lipsius tells him,
"You have loved the Muses, they have loved you, they will love you, and
I too with them will love you." We have still preserved by his son[5] a
translation in verse, made by him in his youth of some Greek verses of
Palladas. He also wrote a Paraphrase on the Epistle of St. John; which
Hugo Grotius mentions in one of his Letters[6].

Four times he was Burgomaster of Delft, and Curator of the University of
Leyden: this last was a place of great consequence at that time. There
are only three Curators in the University of Leyden; one is taken from
the body of the nobility, and nominated by them; the two others are
chosen by the States of the Province from among the cities of Holland,
or the Courts of Justice.

The Curators with the Burgomasters of Leyden have the direction of
whatever regards the welfare and advantage of the University; they chuse
the Professors, and have the care of the finances and revenues for
payment of their salaries.

John de Groot filled the place of Curator with great dignity and honour.
Daniel Heinsius wrote some verses in his praise, in which he styles him
the Apollo and Protector of the Muses.

This dignity did not hinder him from taking the degree of Doctor of
Laws. In the remaining part of his life he attached himself to the Count
of Hohenloo, who made him his Counsellor.