The numbering is for practical reasons to distinguish between different works with the same title.
In Greek mythology, Medea, often portrayed as a sorceress and priestess of the goddess Hecate, plays a crucial role in the myth of Jason and the Argonauts. She aids Jason in his quest for the Golden Fleece, and they subsequently marry. However, when Jason later abandons her for Creusa, the Corinthian king's daughter, Medea exacts a brutal revenge by killing Creusa and her own two sons. Delacroix's famous painting, "Medea About to Kill Her Children," captures the moment before this horrific act. Constant, finding Delacroix's interpretation too ornate, created his own watercolor version, aiming for a more cruel depiction of the scene.
Source: Locher, J.L. Constant: Aquarellen | Watercolors 1975-1995, 1995.