Ferdinand Bol was born in Dordrecht in 1616 and received his initial training as a painter from Jacob Gerristz. Cuyp. Bol seems to have entered Rembrandt's studio about 1637 to study not as an apprentice but as an assistant (his earliest signed painting was done about 1635) and established himself as a master in his own right around 1642. In his paintings, he imitated Rembrandt's style so closely that some of his works were mistaken for Rembrandt's for centuries afterwards. Although his style changed, throughout his career Bol painted many of the same subjects, especially history paintings and portraits. Roseline Bacou, Curator of Drawings at the Louvre, which possesses a number of his drawings, notes that "During his lifetime, Bol's reputation as a portraitist surpassed Rembrandt's" (Great Drawings of the Louvre Museum: The German, Flemish, and Dutch Drawings, trans. Marguerite Hugo [NY: George Braziller, 1968], n. 92).
Bol's etching oeuvre is a small but important part of his work. Almost all of them are studies of people and are often powerful depictions of serious men, usually older – saints or philosophers – who often seem, like Hamlet or Lear, to be pondering the meaning of human existence. This seems to be the preoccupation of the elderly man depicted in this etching, who is also notable for the ornamental trefoil on his coat, as the title suggests. The large volume on his lap further suggests he is a philosopher or theologian.
See: http://spaightwoodgalleries.com/Pages/Bol.html
Dr Mark Stocker Curator, Historical International Art July 2017