Often mentioned as the temple of Nike (victory) this small temple was in fact dedicated to Athena, just like the Parthenon. However, the Parthenon was the temple of Athena the Warrior whereas this was her temple as Bringer of Victory (Athena Nike).
In many ancient fortified citadels we find some sort of temple or shrine to the right of those approaching the entrance. These are always dedicated to gods that protect in battle, which makes perfect sense, if we consider that in case of an attack, the most vulnerable side of the attacker is the right, holding sword or spear, not the left, holding the shield.
For this reason fortification builders always paid special attention to the right side of the gate and the populace placed offerings there to the gods deemed more likely to lend a helping hand. In more peaceful times, the site could well be adorned with a beautiful temple, like this small one, build in the ionic style.
Notice the slender columns and the decorated frieze on top. The temple was recently restored and the scaffolding, that had been covering it for years, removed. Only the bright white marble is new, added by the restoration team. The rest are the original blocks, pieced together again after so long.