Achille: Robust soldier, fragile man

In Greek mythology, Achilles (Ancient Greek: Ἀχιλλεύς, Achilleus) was a Greek hero of theTrojan War, the central character and the greatest warrior of Homer's Iliad.

Achilles also has the attributes of being the most handsome of the heroes assembled againstTroy.

Later legends (beginning with a poem by Statius in the first century AD) state that Achilles was invulnerable in all of his body except for his heel. 

According to the Achilleid, written by Statius in the first century AD, and to no surviving previous sources, when Achilles was born Thetis (his mother) tried to make him immortal by dipping him in the river Styx and making him invulnerable. However, he was left vulnerable at the part of the body by which she held him, his heel. 

Since he died due to a poisonous arrow shot into his heel, the term "Achilles' heel" has come to mean a person's principal weakness

Source: http://en.wikipedia.org/wiki/Achilles

Villa Reale, Milano

We have chosen the character Achilles to represent our pair of antonyms because we think that he represents both of them very well. With his muscular body and strength he represents ROBUST, but his heel shows his real weakness and how FRAGILE  he really is.