Both sides built walls and counter-walls, and the Athenians succeeded in cutting off Potidaea from the sea with a naval blockade. During the blockade, representatives from Corinth, Athens and Sparta met in Sparta, resulting in a formal declaration of war. However, this siege, which lasted until 430/429 BC, seriously depleted the Athenian treasury, with as much as 1,000 talents per year required for the military activity. This was not popular with the Athenians, and in combination with the plague that swept through Athens in the early 420s BC, made the continued leadership of Pericles untenable. The Periclean strategy of hiding behind the Long Walls and relying on the low cash reserves of the Peloponnesians was starting to become unfavourable to the greater Athenian consciousness. In several of Plato's dialogues, the philosopher Socrates is revealed to be a veteran of the Battle of Potidaea, where he saved the life of Alcibiades ("Symposium" 219e-221b).