Threats Mongol raids posed a serious challenge to Ala-ud-din. During the second year of his rule ( ), when Mongols stormed Delhi, the army sent by Ala-ud-din succeeded in driving them back. But when they returned the following year with more men, people of the suburbs of Delhi had to flee and take refuge in the city. Ala-ud- din had to meet the problem head-on.
In the ensuing battle, Mongols were routed. Yet raids continued until , when they ravaged the doab region. This time, after defeating them, the Sultan’s army took a large number of Mongols as prisoners and slaughtered them mercilessly. But the Mongol menace continued.
The last major Mongol incursion took place in – . Ala-ud-din Khalji (modern representation) Balban succeeded in obtaining from him the assurance that Mongols would not advance beyond Satluj. Halagu Khan reciprocated this gesture by sending a goodwill mission to Delhi in . However, Muhammad Khan, the favourite son of Balban, who was given the charge of governor of Multan to protect the frontiers from Mongol aggression, was killed in an encounter.
Saddened by this tragedy, Balban fell ill and died in .