"Pyrrhus won two major battles against the Romans in 280 and 279, respectively. But he took such heavy casualties in those battles that he would eventually lose the war — giving rise to the term "Pyrrhic victory."
"The first conflict occurred after Carthage intervened in a dispute on the island of Sicily, just off the southern tip of Italy. While Sicily wasn't Roman territory at the time, the Romans felt this was a little too close to home. They sent an army to expel the Carthaginian troops. The result was the First Punic War, which lasted for more than 20 years. This map shows the situation after the war: Rome gained control of the islands of Sicily, Corsica, and Sardinia making it a significant naval power for the first time."
"The Romans put their least experienced soldiers in the front line (the bottom in this picture), in hopes that the enemy would waste energy fighting them, making them too exhausted to put up a fight when they reached more experienced (and better armed) soldiers further back."
Compare this to putting the least experience in the middle between strong men. In the Iliad king Agamemnon does this to prevent cowards from fleeing.