Yazd is the capital of Yazd Province, Iran, and a centre of Zoroastrian culture. The city is located 270 km (170 mi) southeast of Isfahan. At the 2006 census, the population was 423,006, in 114,716 families. Because of generations of adaptations to its desert surroundings, Yazd is an architecturally unique city. It is also known in Iran for the high quality of its handicrafts, especially silk weaving, and its confectionary.The city has a history of over 3,000 years, dating back to the time of the Median empire, when it was known as "Ysatis" (or "Issatis"). The present city name has however been derived from Yazdegerd I, a Sassanid ruler. The city was definitely a Zoroastrian centre during Sassanid times. After the Arab Islamic conquest of Persia, people periodically faced extreme religious oppression including forced conversions, massacres, harassment, and other forms of discrimination, and then many fled to Yazd from neighbouring provinces. By paying a levy, Yazd remained Zoroastrian even after its conquest, and Islam only gradually became the dominant religion in the city.Because of its remote desert location and the difficulty of approach, Yazd had remained largely immune to large battles and the destruction and ravages of war. For instance, it was a haven for those fleeing from destruction in other parts of Persia during the invasion of Genghis Khan. It was visited by Marco Polo in 1272, who remarked on the city's fine silk-weaving industry. In the book 'The Travels of Marco Polo', he described Yazd in the following way: "It is a good and noble city, and has a great amount of trade. They weave there quantities of a certain silk tissue known as Yasdi, which merchants carry into many quarters to dispose of. When you leave this city to travel further, you ride for seven days over great plains, finding harbour to receive you at three places only. There are many fine woods producing dates upon the way, such as one can easily ride through; and in them there is great sport to be had in hunting and hawking, there being partridges and quails and abundance of other game, so that the merchants who pass that way have plenty of diversion. There are also wild asses, handsome creatures. At the end of those seven marches over the plain, you come to a fine kingdom which is called Kerman."