The Chigi vase, found in an Etrsucan tomb, is the earliest representation of the Hoplite phalanx formation. Dated 650 B.C.
The hoplite phalanx operated as follows: They would be in a tightly-packed formation, with each soldier’s shield protecting his left side and the right side of his soldier on his left.
On the vase we see a musician boy playing the double flute behind the Spartans, which set their slow pace towards the enemy.
When the two opposing armies met each other, the front rows would slam into the enemy in front of them as they tried to push through the wall of shields, as depicted in the vase. The rows towards the back would push their shields into the backs of the soldiers in front to drive their men further into battle. It would be comparable to rugby scrums we see today.