Michael was born into the gens (clan) Nánabeszter, which possessed landholdings along the river Danube in Central Hungary, in the surrounding area of the royal capitals Esztergom and Buda.
Michael had two sons: Thomas inherited his wealth but died without descendants, ending the line of Nánabeszters,[1] while Lawrence entered ecclesiastical career and served as Provost of Požega from around 1288 until his death.
[2] When Michael first appeared in contemporary records in 1243, during the reign of Béla IV of Hungary, he already functioned as ispán of Veszprém County.
[4] Michael bought a portion of Érd with half of the island and six servants belonging to it from John, son of Thaddeus Érdi before the collegiate chapter of Buda in 1243.
[8] Their relative, Nana III sold one of his servants, who lived in his estate Sasad (today a borough of Újbuda, Budapest), to Michael and Stephen in 1256.