The evidence of the witnesses on the trial agrees with the testimony afforded by the chronicles: it is plain that Gutenberg had not perfected his invention in 1439. From his lonely room in the ruined monastery of Saint Arbogastus, to which he retreated for the sake of secrecy, Gutenberg gave work to Dünne, the goldsmith, to Saspach, the joiner, and to Dritzehen, his old workman. It would seem that they were not producing work for sale, but were making tools which required a great deal of labor. Dritzehen worked night and day, Madame Schultheiss helping him. At the death of Dritzehen, the work expended on the art had cost a great deal of money, but it was still incomplete. The testimony shows that it had been intended that the salable work to be produced by the partnership should be exposed for sale at the great fair of Aix-la-Chapelle in the summer of 1439. The postponement of this fair[239] to the year 1440 was a grave disappointment. If the object of the partnership was the making of popular books of devotion, we can understand the reasonableness of the hopes of great profit when the books should be laid before the pious pilgrims. The sudden death of Andrew Dritzehen was the occasion of more delay. Gutenberg, fearing that the public, or George Dritzehen, would get possession of the secret, melted the forms and suspended the work. Then followed a litigation which lasted nearly one year, during which period it seems no work was done. [Illustration: A Medieval Press. [From Duverger.]] There are many conflicting opinions about the character of the printing so obscurely mentioned in the testimony of the witnesses. Schoepflin says it was block-printing. In the four pieces lying in the press, he sees four pages of engraved [p395] blocks; in the two buttons, which Dr. Van der Linde says are improperly translated by him as two screws, he finds a screw chase that held the four pages together. This conjecture is in every way improbable. All the processes of block-printing should have been as well known at that time in Strasburg as they were in Venice, Augsburg and Nuremberg. Something more novel than this form of printing would have been required to secure the coöperation of shrewd men like Riffe and Heilmann. The enthusiasm of Dritzehen, and the eagerness of all parties to learn the new art, and to have a share in its profits, cannot be satisfactorily explained by the conjecture that this art was simple block-printing.[240] [p396] Gutenberg may have begun his experiments in typography by the use of engraved types or punches of wood;[241] but he must have soon discovered the defects and limitations of xylography and have reached the unalterable conclusion that useful types could be made of metal only.