In Sketches of the heads of witnesses to the death of St. Matthias to the painting ‘Martyrdom of St. Matthias’, we see a collection of expressive faces.

The figures are rendered with careful attention to detail, showcasing a range of emotions from sorrow to shock. The use of ink creates a stark contrast, emphasizing the solemnity of the scene. The background is minimal, focusing the viewer's attention on the witnesses' faces. This work is executed in ink on paper, a medium that allows for fine lines and intricate details.

The dimensions are approximately 25 x 35 cm, making it a relatively small piece. The drawing captures the moment of witnessing a significant event, reflecting the artist's skill in portraying human emotion. The lines are fluid, and the shading adds depth to the expressions. Józef Simmler was a Polish artist known for his historical and religious themes.

This particular work serves as a preparatory study for a larger painting, ‘Martyrdom of St. Matthias’. It highlights Simmler's interest in the human experience during pivotal moments.

An interesting fact is that Simmler often focused on the emotional responses of figures in his works, making them relatable and impactful.