In 1866, Joseph Joachim visted the ‘Kensington Museum, which today we know as the Victoria and Albert. He was particular impressed by a wax cast taken from a clay model by Michelangelo in the Casa Buonarotti, Florence. This is sometimes regarded as a study a) for a Hercules and Cacus group commissioned in 1528, b) for a group planned after 1530 for the Tomb of Pope Julius II, and c) for a Samson and the Philistine on which Michelangelo was working in 1528-9.
He wrote to his friend, the Michalangelo scholar, Hermann Grimm:” The ‘Hercules and Cacus are powerful. The whole thing is only roughly sketched on a small scale. In the former, the head and arm are wanting. The body seems to me to stand there in conscious power, ready for action; and, by the movement of the shoulders, and the bending of the strong back, we see how well able he was to wield the club, which was to give the deathstroke to Cacus, who lies there, held down by the right knee of the demi-god, vainly endeavoring by the movements of his left leg to entangle the left leg of Hercules, while his right arm involuntarily tries to avert the death-stroke from his head. The whole figure is like a coil,— a striking contrast to the powerful, victorious hero who had cast him on the ground.”