It was an industrializing mercantile hub with many jobs for people with little command of the English language. The waves of immigration resulted in tensions in the city with native-born residents, who had to compete for work in difficult economic times. Anti-Catholic riots took place in the 1830s and 1844, in the Philadelphia Nativist Riots, occurring as Irish Catholics began to arrive in significant numbers in the city. Soon more riots occurred, mainly since the town was a stronghold of the Know-Nothing political party, known for its anti-immigrant and anti-Catholic prejudices.