She was a younger sister of Irene Lascarina, first Empress consort of John III Doukas Vatatzes. Theodore was widowed in the same year and proceeded to marriages with Philippa of Armenia and Marie de Courtenay. However John was never displaced in succession.
As a younger daughter, the marriage of Maria was not intended to add a potential husband in the line of succession to the throne.
Instead it secured a marital alliance with the Kingdom of Hungary. In 1218, Maria was married to prince Béla of Hungary.
Bride and groom were about twelve-years-old. Her husband was the eldest son of Andrew II of Hungary and Gertrude of Merania.
Andrew II died on 26 October 1235.
The crown prince succeeded him as Béla IV and Maria became queen. Béla reigned for thirty-five years and died on 3 May 1270. Maria survived him by about two months.