The era of Seljuk Turk rule over Persia in the 11th and 12th centuries. According to a common account of rug history, the new rulers brought weavers highly skilled in the Turkish (Ghiordes) knot and so introduced it to Persian weaving, an influence still seen most strongly in rugs from Tabriz, Azerbaijan and Hamadan. The knot itself, however, is far older than Seljuk rule.