From 1724 he lived in the monastery of Krasnystaw, where he engaged in his life's work, compiling the Herbarz Polski (Polish Armorial).

Niesiecki wanted to write it in Latin, but his patron, Marianna from Potocki-Tarłowa, specified that it was to be published in Polish.

Because Niesiecki tried to not use unverified sources and legends, he was opposed by the szlachta (Polish nobility).

After the fourth volume was published attacks by the nobles increased; they sent letters of protest to his Polish and Roman superiors.

[2] In the 19th century the armorial was expanded by several authors and published by Jan Nepomucen de Bobrowicz in Leipzig.