Year 498 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Siculus and Flavus (or, less frequently, year 256 Ab urbe condita). The denomination 498 BC for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
Athens and Eretria respond to the Ionianplea for help against Persia and send troops. An Athenian and Eretrian fleet transports Athenian troops to Ephesus. There they are joined by a force of Ionians and march upon Sardis, the capital of Artaphernes (the satrap of Lydia and brother to Darius I of Persia). Artaphernes, who has sent most of his troops to besiege Miletus, is taken by surprise. However, Artaphernes is able to retreat to the citadel and hold it. Although the Greeks are unable to take the citadel, they pillage the town and set fires that burn Sardis to the ground.
Retreating to the coast, the Greek forces are met by the Persians under Artaphernes and defeated in the Battle of Ephesus.