Our Prophet (saas) foretold that a sedition that would threaten Muslims’ lives and possessions would appear

Muslims’ blood will be considered lawful. Both their blood and possessions will be considered lawful…It will shake the world like the waves in the sea. No one will find any refuge. (This sedition) will arise from Shaam and spread all over Iraq. It will inflict a blow all over the Arabian peninsula with its hand and foot. Just as leather dealers pull leather, all Ummah will receive a blow and scourges will come. A person will not be able to find the might to say “stop” to this sedition. If they stop the problem in one region, it will appear from another place. (  Nuaym b. Hammad)  

Mahdi appears when Sufyan reaches Kufa and kills the helpers of Ali Muhammad and Shuayb bin Salih Tamimi becomes his standard bearer. (Imam Suyuti )

That man from Tamim called Shuayb bin Salih defeats the men of Sufyan. He descends all the way down to Bayt al-Maqdis and lays the ground for Mahdi’s dominance: 300 people from Shaam help him. Between his appearance and submission of the duty to Mahdi, there exists a period of 72 months. ( Fatawa-i Hadîsiyya, Ibn-i Hajar Haytami -42)