Risking the Umayyads’ wrath, the commemoration of Karbala was initially small and private. In particular, pilgrimage to Karbala remained limited and precarious during this period. Soon after the Umayyads fell, however, Shia imams worked to institutionalize the Ashura and Arba’in pilgrimages to the tomb of Husayn. This attempt is reflected in some of the traditions ascribed to the imams. For instance, the Shia imam Hasan al-Askari (d. c. 874) is reported to have listed the Arba’in pilgrimage among the five signs of a true believer.