[1] In 1522, Jan van der Cruyce, a graduate of the University at Leuven and a friend of Erasmus, travelled to England to become a private tutor to Mountjoy's children.
In 1523 Juan Luis Vives wrote a short educational treatise dedicated to Charles, De ratione studii puerilis ad Carolum Montioium Guilielmi filium.
After the dissolution of Syon Abbey in 1539 Mountjoy granted asylum at his London house to the pious, learned, and outspokenly conservative priest Richard Whitford, who had been patronized by his father.
Like his father, Mountjoy was deeply interested in the humanist educational programme and he tried to engage the learned scholar and educationist Roger Ascham, then teaching at Cambridge, as a tutor to his eldest son and secretary to himself.
In it, he admonished his children to "kepe themselfes worthye of so moche honour as to be called hereafter to dye for there maister and countrey" (PRO, PROB 11/30, fol.
After being present with Henry VIII at the siege of Boulogne, he died on 10 October 1544 at Hooke, Dorset (formerly the home of his mother), probably from an illness contracted on campaign.