Ludovicus Nonnius (1553 - 1645) was a friend of Rubens. He was a doctor and antiquarian from a Portuguese family who worked in Antwerp. The book he holds and the objects surrounding him refer to his accomplishments. The sitter wrote a number of works, of which his best known the 'Diaeteticon sive de recibaria, Libri IV' (Antwerp 1627), has been claimed as the first book to treat diet as an important factor in health. It was based upon the eating habits of the ancient Romans. The presence of the bust of Hippocrates (the Greek founder of medicine) identifies his profession and his respect for Antiquity - a vital aspect of contemporary learning.
The portrait is dated to the late 1620s on grounds of style. It was probably painted shortly before Rubens's diplomatic journeys of 1628-30, and may date from the year of publication of the 'Diaeteticon', which could be the book the sitter holds.The bust is based upon a drawing after the antique by the artist which was the subject of an engraving by Schelte à Bolswert of 1638.