at discouraging rebellion is uncertain. Just a few years after the conquest of Melos, Athens suffered a devastating defeat in a military expedition to Sicily, after which rebellions happened throughout the empire. Whatever benefit the conquest of Melos produced was wiped away by the disaster that happened in Sicily. Whether Melos was truly neutral is sometimes debated by scholars. Thucydides wrote that after the raid by Nicias in 426 BC, the Melians assumed "an attitude of open hostility", but neither Thucydides nor any other writer of the era mentioned any specific offence that Melos committed against Athens. There is archaeological evidence that Melos once donated some money to Sparta (at least 12½ kg silver), but it's uncertain whether this donation happened before or after the raid by Nicias. Melos is typically regarded by scholars to have been an innocent victim of Athenian imperialism. The islands of the Aegean Sea provided valuable tax revenue for Athens, but what was probably more vital was naval access to their ports. Warships of the era (triremes) could carry little in the way of supplies and had no sleeping space for the crew, and thus needed to stop in port on a daily basis to buy supplies, cook meals, and camp for the night. Triremes were also not particularly seaworthy and thus needed harbors to shelter from rough weather. A trireme could normally travel around in a day whereas a trip from Athens to Asia Minor is roughly . Thus, in order to control the Aegean, Athens needed to secure exclusive access to the islands' ports for its navy. If Melos was neutral, enemy ships could resupply there, so capturing it denied that to Athens' enemies. The Athenians had shown mercy to their defeated enemies in the earlier years of the Peloponnesian War, and in preceding wars. For instance, after putting down the rebellious city of Potidaea in 429 BC, the Athenians spared the surviving Potidaeans and allowed them to leave the city. As the war dragged on, the Athenians came to feel that leniency made them look weak and encouraged revolts. The rising brutality of the Athenians was also a response to Spartan brutality, which had been extreme from the beginning. In particular, it was after the massacre committed by the Spartans at Plataea in 429 BC that the Athenians habitually massacred their own prisoners. Even so, the massacre of the Melians shocked the