He was 5 years old when his father died and was raised by his uncle Atabeg Ivane, who converted him to the Chalcedonian faith.

Rubroek, envoy extraordinary of King Louis IX of France to the Khan of Mongol Empire, stayed in 1255 with Shahnshah on one of his Armenian estates.

[6] The combined troops went on to Ani, the Armenian capital defended by Shahnshah Zakarian, but the city was eventually captured and destroyed.

[6] Following this disastrous campaign of 1238-1239, the Armenians and Georgians made peace with the Mongols and agreed to pay them tribute and supply their troops (Georgian–Mongolian treaty of 1239).

[7] In 1259-1260, Shahnshah Zakarian participated to the Mongold-led Siege of Mayyāfāriqīn, together with the Armenian Prince Prosh Khaghbakian and Avag.