The social origins of Islamists changed after the 1952 Revolution. In the 1940s and early 1950s, the Muslim Brotherhood had appealed primarily to urban civil servants and white and blue-collar workers. After the early 1970s, the Islamic revival attracted followers from a broad spectrum of social classes. Most activists were university students or recent graduates; they included rural-urban migrants and urban middle-class youth whose fathers were middle-level government employees or professionals. Their fields of study—medicine, engineering, military science, and pharmacy—were among the most highly competitive and prestigious disciplines in the university system. The rank-and- file members of Islamist groups have come from the middle class, the lower-middle class, and the urban working class.