For the next 30 years, after the collapse of Azerbaijan's autonomous government, Tabriz enjoyed a stable era until the revolution in 1979. During this period the city received many of investors in its industries and had transformed into a heavy industries hub in the northwest of Iran. The need for a strong workforce increased immigration from all around Azerbaijan toward Tabriz. During this era and because of the continuous policy of the government centralization in Tehran as well as changes in communication and transportation, the city lost its historical dominance in favour of being the gate for reform and modernization in the country.