‘It is the finest equestrian portrait I have ever seen’, Marées wrote to Schack in 1865 from Florence. The painting in the Palazzo Pitti is a replica, much reduced in size, of a picture by Velázquez now in the Prado in Madrid. Translating the original into his own pictorial idiom, Marées confirmed Schack’s belief that ‘A copy can be a true and genuine work of art because, if it is good, it is not produced in a mechanical way, but requires considerable artistic force to bring it to life.’