Many of the ornamental processes which we admire in Venetian glass were already in use in this century.
An elaborate account of the processes of making the vitro di trina and the vasi a reticelli (Plate I., fig.
He was especially successful in making vases and circular dishes of vitro di trina; one of the latter in the Correr collection at Venice, believed to have been made in his glass-house, measures 55 centimetres (nearly 23 in.) in diameter.
In the controversy about election, when appealed to by Charles the Bald, Ratramnus wrote two books De praedestinatione Dei, in which he maintained the doctrine of a twofold predestination; nor did the fate of Gottschalk deter him from supporting his view against Hincmar as to the orthodoxy of the expression "trina Deitas."
To refute the predestinarian heresy Hincmar composed his De praedestinatione Dei et libero arbitrio, and against certain propositions advanced by Gottschalk on the Trinity he wrote a treatise called De una et non trina deitate.