As pointed out by Professor Werner Sumowski (loc. cit.) and confirmed by Dr. Peter van den Brink (verbal communication), this picture can be dated by subject matter and style to the early 1620s, comparable to such paintings by Backer as An old man in profile in the Gemäldegalerie, Dresden, and An old man in religious dress in the Hermitage, Saint Petersburg.
Backer's figures were influenced by those in Lambert Jacobsz.'s monumental history paintings of the early 17th Century, for which he blended Rubenesque and Utrecht Caravaggist tendencies. Yet, in contrast to Jacobsz., whose figures' weight and expression draw from their poses and monumentality, Backer focused on the facial expression of his subjects. He often based these on detailed preparatory studies, such as the drawing of a head that was the model for the heads in the Dresden and Saint Petersburg pictures (see W. Sumowski, Zeichnungen der Rembrandt Schüler, 1979, I, no. 2). As the head in the present picture is identical to the one of Hippocrates in the Democratus and Hippocrates of circa 1630 (Bader collection, Milwaukee; see W. Sumowski, op. cit., 1983, p. 193, no. 3, illustrated), it could similarly have been based on a model drawn from life. A possible candidate could be the Study of a bearded man (see W. Sumowski, op. cit., 1979, p. 190, no. 22).
Professor Werner Sumowski has suggested that the figure in the present painting might be an apostle or a philosopher of antiquity, possibly Saint Paul, whose writings contributed significantly to the doctrine of the Reformed church in the Northern Netherlands and who might have had a great appeal to Backer, who was from a Mennonite family.