Castaldi, more ingenious or more fortunate, had already discovered movable types before the arrival of Faust in Feltre. It is well known that, a century before the publication of the _Mentz Psalter of 1457_, initial letters and capital letters formed of glass were manufactured at Murano, and used in Italy. These glass letters were, probably, the invention of Pietro de Natali, bishop of Equilo. Castaldi had noticed that these letters were of advantage to the scribes, who printed them in their manuscript books. He at once saw that it would be possible to print entire books, instead of occasional letters, with movable types. The facility with which this discovery had been made caused him to undervalue its importance. He gave the idea to Faust, who, returning to his partners in 1456, or a little before, enabled them to appropriate the invention of Castaldi. They greedily adopted this invention, and, in 1457, they produced the _Psalter_, the first book printed with movable characters of wood.[336] The only portion of this absurd story which has any claim to respect is that about the early use in Italy by copyists of engraved or moulded initial letters. That they were, or could have been, made by the glass-blowers of Murano, and that Castaldi may have amused himself with experiments in stamping consecutive letters or lines, is possible. All else is pure fiction. It does not appear that Castaldi printed anything of value: we have no relics of his experiments in the form of a book, or even of a leaf, a line, or a letter. Nor did his dreams or teachings about the possible value of types ever incite any of his Italian pupils to make and use types. To those who think that the merit of the invention of printing is in the conception of the idea of movable types, this legend about Castaldi is instructive. It reveals to us a man who is represented as having a very clear idea of the [p488] importance of types, who did nothing with his great discovery. His discovery, if it can be so called, was useless. He cannot be rated as an inventor of printing, for he printed nothing. John Mentel, of Strasburg, who died in December, 1478, and was buried in the great cathedral of that city, has there a tablet to his memory, which contains the following inscription: Here I rest: I, John Mentel, who, by the grace of God, was the first to invent, in Strasburg, the characters of typography, and to develop this art of printing, which should be perpetuated to the end of the world, to such a degree of perfection that a man can now write as much in a day as another could have done in a year. It is but just that thanks should be rendered to God, and without vanity, to me myself; but as this homage could not otherwise be rendered in a proper manner, God has ordained, as the reward for my invention, that the stones of this cathedral should serve for my mausoleum.[337]