On the traditional French upright loom the weaver performed the keeping apart of the warp threads above her head by means of a manually-worked heald or heddles. Every even warp thread was held by one of these and every odd thread by another. Between warp threads held open in this way coloured weft threads were led across. From engravings published in Diderot’s Encyclopaedia (1751- 1772) we have an exact picture of a French workshop of the time. After the elimination of this succession of uncomfortable movements, the tredle-operated upright loom took root in Hungary, created by György Korody. In French workshops they adhere to the traditional loom even today. Tapestries woven on an upright loom can be checked as the weaving work continues. The width of a loom could be as much as several metres in many cases. Individual weaving workshops usually favour a particular type of loom.