Faisalabad was founded in 1880 as Lyallpur, and named after then British Governor of the Punjab. It was renamed Faisalabad in 1977 after the late king Faisal of Saudi Arabia, who had displayed considerable generosity to Pakistan.
In 1902 it still only had 9,000 people but, thereafter the  growth of commercial farming and cotton cultivation, South Asia's great tradition of textile production, and the settlement of East Punjabi refugees after 1947 led to explosive growth. Today the city has almost 3 million people and district more than 5 millions. A large proportion of the population some say majority are East Punjabis who replaced local Hindus and Sikhs who fled in 1947. Faisalabad is therefore, partly at least example of economic dynamism of these migrants, even while it also reflects their cultural conservatism.

Source: Pakistan A Hard Country