Although the earliest recorded counting device was the abacus, the oldest surviving calculation tool is the Salamis tablet. This object is named after the Greek island where it was found in the 19th century. The Salamis tablet was no pocket calculator: a marble slab measuring 150 x 75 x 4.5 cm. (59 x 29,5 x 1,7 in.) and weighing 130 kg. (286 lb.), it was used in Babylon as early as 300 BC. As an object, the tablet has the extreme simplicity of the raw material: a stone piece with etched elements, it was originally thought of as a gaming board. Gaming is, after all, counting. The tablet’s two sets of grooves –and spaces in-between them- are used in conjunction with pebbles or beads, and the symbols in the periphery, to create a well-determined system that allowed users to consistently perform the four basic operations of addition, subtraction, multiplication and division. The Salamis tablet offered rigor and permanence to the important act of counting. The selection of durable and monolithic marble and the effort of etching a system in it to allow for the same process to take place over and over again, represent in itself a major proof of design evolution. Durability and predictability allow a spectacular process of innovation –over the centuries- from the ad-hoc system of temporary markings in clay surfaces, to a well-designed object that insures an established protocol and the consistent repetition of the same action.
