In the years around 1650 the problem of exactly dating the pictures increases, and they have to be grouped together stylistically. Thus it is usually possible to be accurate to within five years or so by looking very carefully at a dated picture and grouping round it all the obviously similar undated ones. The artist concentrated on a series of heads of different types of people. Many versions of the Head of Christ exist, the one chosen here is now in the Gemäldegalerie in Berlin. There is a certain element of sentimentality in this series of heads-the sad eyes and the handsome bearded face.
The unlikely suggestion has been made that Rembrandt was Jewish; if so, he took the Christian religion seriously. But more likely he belonged to one of the obsure Protestant sects which sprang up in Amsterdam at the time, and which laid great emphasis on the reading and understanding of the Bible. If Rembrandt really did belong to the Mennonites it is almost as though these heads of Christ were painted for devotional purposes. They are usually of the same sitter, and there are versions in the Bredius Museum at The Hague, the Detroit Institute of Arts, Berlin, Philadelphia and in the Fogg Museum at Harvard.