The area around Lake Balaton was settled as early as the Iron Age and the Romans, who called the lake Pelso, built a fort at Valcum (now Fenékpuszta), south of Keszthely, in the 2nd century AD. Throughout the Great Migrations, Lake Balaton was a reliable source of water, fish, reeds for thatch and ice in winter. The early Magyars found the lake a natural defence line, and many churches, monasteries and villages were built in the vicinity. In the 16th century the lake served as the divide between the Turks, who occupied the southern shore, and the Habsburgs to the northwest, but before the Ottomans were pushed back they had already crossed the lake and razed many of the towns and border castles in the northern hills. Croats, Germans and Slovaks resettled the area in the 18th century, and the subsequent building booms gave towns such as Sümeg, Veszprém and Keszthely their baroque appearance.
Balatonfüred and Hévíz developed early as resorts for the wealthy, but it wasn't until the late 19th century that land- owners, their vines destroyed by phylloxera lice, began building summer homes to rent out to the burgeoning middle classes. The arrival of the southern railway in 1861 and the northern line in 1909 increased the tourist influx, and by the 1920s resorts on both shores welcomed some 50, 000 holiday-makers each summer. Just before the outbreak of WWII that number had increased fourfold. After the war, the communist government expropriated private villas and built new holiday homes for trade unions. Many of these have been turned into hotels, greatly increasing the accommodation options.