Chittor was besieged in 1303 AD by the army of Alauddin Khilji, sultan of Delhi, who is said to have coveted Padmini, Rani of Chittor, a legendary beauty of her day. The famous Jauhar followed, wherein Rani Padmini, led the ladies of the fort into death by self-immolation. The next morning, the menfolk of Chittor rode out to face certain death on the field of honour.
After Chittor was lost, an extremely distant kinsman of Rawal Ratan Singh (Rana of Mewar), by name 'Laksha' or Lakshman Singh, proclaimed himself Rana-in-exile. Laksha was descended in direct patrilineage from Bappa Rawal (founder of Mewar Dynasty), and hence belonged to the Gehlot clan. But he was an eighth cousin twice removed of Rawal Ratan Singh. Laksha hailed from the village of Sisoda near the town of Nathdwara. Laksha was the father of nine sons, of whom the eldest was Ari. Hammir was the only child of Ari.
Both Laksha and Ari died in various skirmishes when Hammir was yet an infant; resultantly, Hammir grew up under the tutelage of his uncle Ajay, the second son of Laksha.
The Khiljis had assigned their newly conquered territories to the administration of Maldeo, ruler of the nearby state of Jalore, who had allied with them during the recent war. In a bid to reconcile and co-opt the natives of the land to his rule, Maldeo arranged for the marriage of his widowed daughter Songari with Hammir. Rana Hammir Singh re-established the state of Mewar in 1326 by engineering a coup d'état against his father-in-law. The dynasty thus founded by Hammir, who was descended in direct patrilineage from Bappa Rawal, came to be known as Sisodia after Sisoda, the mountain village whence Hammir hailed.