A positioning device and a fastening device to fix the relative position of two or more adjacent tiles on a tiled display and to provide alignment. Fixing the relative position of two adjacent display tiles will facilitate the alignment of tiles in tiled displays where the seam between tiles will be as regular as possible, thereby avoiding the introduction of misalignments and their associated visual artefacts. The positioning device allows linkage of it to at least two tiles of a tiled display. The display tiles are often rectangular in shape and the positioning device is then located at a corner of the tile. The positioning device can also be attached to a support structure to make a tiled display.