Before the invention of printing, the copies of block-books were obtained, as has been already mentioned, by what is known as the _frotton_ process, the paper being placed over the engraved block and rubbed with a special pad. The ink in the originals is of a brownish yellow. After the invention of the press, certain popular treatises continued to be struck off from xylographic cuts, but by impression, like ordinary books. One of these, the _Mirabilia Romae_, a guide-book to Rome at the end of the fifteenth century, has a large historiated S at the beginning. It is remarkable from the fact that the letterpress, of which a specimen is given with the initial, is not cut in imitation of type, but, as can be seen in our reproduction, of ordinary hand-writing. Another specimen of this kind of printing is the P, which we reproduce with a border, from a Donatus, the first and eighth leaves of which were preserved for centuries in an old binding. This Donatus, of which the only leaves remaining belong to the Leipsic Museum, was printed by Dinckmut. There is another xylographic fragment with a colophon bearing the same name in the Bodleian Library. The initial itself represents a schoolmaster surrounded by his pupils, a subject frequently met with as a frontispiece to books of this class, and it is prolonged into a border which frames the page. When the initial of a Donatus does not represent a pedagogue and his class, the subject is often the Virgin and Holy Family. J. Rosenthal has an extremely valuable edition with the Virgin, the Child, and St. Catherine. Amongst our specimens of Cologne is a Donatus without name of printer or date, but no doubt printed by Quentell towards 1500, in which, besides the Virgin and Child, there are grotesque profiles in the two left corners which look as if copied from the same source as one of the Bämler initials, and the initial with grotesques in the Bâle Psalters.[9] [9] The Donatus, always being in demand, was generally one of the first books printed at a new press. It was the first work issued by Pannartz and Sweynheim when they started at Subiaco. During the remainder of the fifteenth century there was very little in the way of initial ornamentation in books published at Mayence, where Scheffer, who was always the chief printer, seems to have exhausted his possibilities in this direction with his first experiment. There is, however, a fine large historiated D in a German translation of Æsop--_Das Buch und Leben des Fabeldichters Æsop_--without printer’s name or date, but attributed to Scheffer, towards 1480. This initial has already been reproduced in Muther’s _Bücher-Illustration_, and more recently in a bibliography of incunabula and books printed before 1501, by Ludwig Rosenthal. The only other interesting ornamental letter we are acquainted with of Mayence origin before 1500 is the G at the commencement of Erhardt Reuwich’s _Breidenbach_.