Ghaibat-us-Sughra means â€˜the minor concealment.â€™ Its period was about 70 years. It began in 260 A.H. when Imam al-Mahdi (a.s) first went into concealment, and ended in 328 A.H.
During Ghaibut-us-Sughra, the Imam appointed some agents to represent him and the people. The Imam had four agents. After the death of the fourth agent, the Imam went into major concealment (Ghaibut-ul-Kubra). This was on the 10th Shawal 329 A.H.
Adapted from: “A Short History of the Lives of The Twelve Imams”