Jan Mier (1740–1790) was an Austrian count, a member of the Galician Sejm from the group of magnates, and a cavalier of the Order of St. Stanislaus and the White Eagle. Jan Mier was the court physician of Stanislaw August Poniatowski, the last King of Poland. He was a younger brother of Jozef Mier, the elder of Busk. The portrait depicts a waist-length image of Jan Mier dressed in a uniform. The artist realistically depicted a tired face with a double chin, a high forehead, and thin lips. On Jan Mier's head there is a fashionable light-coloured wig "en catogan". Ostap Biliavskyi managed to depict the image of a strong-willed, determined, restrained, and experienced man. A white camisole can be seen from under the unbuttoned uniform. There is a blue ribbon of the Order of the White Eagle over his shoulder; a cross of the Order of St. Stanislaus hangs on his chest. On the back side of the portrait there is an inscription: “Bielauski, pix 1787. Isopoli Krabia Mior. Kasztelan Inflantski".