One of his main weaknesses was a habit of boasting and exaggerating his own powers, which at first imposed upon a vulgar audience and then left them under the impression that he was a charlatan.

The bookseller Ciotto learned from students who had conversed with him at Frankfort, that 'he professed an art of memory and other secrets in the sciences, but that all the persons who had dealt with him in such matters, had left him discontinued.'[106] [Footnote 104: Mere correspondence with heretics exposed an Italian to the Inquisition.

Residence in heretical lands, except with episcopal license, was forbidden.

The rules of the Index proscribed books in which the name of a heretic was cited with approval.] [Footnote 105: Bruno speaks himself of 'arte della memoria et inventiva' (_op.

cit._ p.