Large machine-processable letters (1) are placed with the stamp (3) at the top in a sorting station (10) on a conveyor means that leads them to further processing stations, has a reference edge (6) in the transport direction and is inclined in the transport direction. The letters are placed in such a way that the letter edge parallel to the address lines, in the proximity of which the stamps (3) are located, lies against the reference edge (6). The stamps (3) are automatically postmarked by a postmarking device (4) arranged tightly over the conveying means (7), at a lateral distance from the reference edge (6) which corresponds to the distance between the stamp (3) and said letter edge. A locally fixed rotation element (8) then turns through 90 DEG the large letter (1) as it is further conveyed so that the shorter letter edge lies against the reference edge (6). |