This is quite a rare find! It is a modello, a preliminary oil sketch, by Sebastiano Conca, a prominent Baroque artist. Modellos served as detailed drafts or studies that artists created before executing the final paintings. They allowed the artist to explore composition, lighting, and color. This practice was not uncommon among artists of the time, who often had to present their ideas to patrons for approval before proceeding to the final piece.

This modello depicts the Holy Family with the Infant Saint John the Baptist, a common theme in Christian art which Conca has approached with a tender intimacy. The softness of the figures' flesh, the gentle expressions, and the subdued palette are typical of Conca's work, who was known for his ability to convey religious narratives with a human and accessible warmth.

The use of mirror writing in the modello is an intriguing detail. It suggests that this study may have been intended as a design for a print or for transfer onto another surface where the image would be reversed back to the intended orientation. When creating prints, the image must be carved or etched in reverse, so that when it is printed, it appears correct. Similarly, if the modello was used to transfer its composition onto a fresco wall or another canvas, the reversed writing would ensure the text appeared properly in the final work.

The existence of a final oil painting with the image in the correct orientation further supports the idea that this modello was part of the planning process. It allowed Conca to finalize his vision before committing to the more labor-intensive and costly process of painting on canvas.