The painting's subject is a life-size[2] swan (Cygnus olor) defending its nest against a dog.

[3] By 1800 when it was purchased, the painting was interpreted as a political allegory of grand pensionary (the highest official in Holland, the main province of the Dutch Republic) Johan de Witt protecting the country from its enemies.

[4] The painting was purchased by the art dealer Cornelis Sebille Roos for 100 guilders for the Nationale Konst-Gallery in The Hague, on behalf of the director Alexander Gogel.

[8] Current speculation is that the white text that was added to the painting in the 1750s during Witten-Oorlog, a pamphlet war between historians.

[9] Its painter Jan Asselijn was assumed to have written the words himself until the timeline was brought into question.