On 22 April 1629, fire took forty-four buildings out of Ærøskøbing. That single afternoon explains why almost nothing medieval survives here, despite the town having been the island's commercial and maritime hub since about 1250 — founded in a period when Ærø answered to the margraves of Brandenburg, and handed back and forth between duchies for centuries afterwards. What followed the fire was not just repair but expansion. Merchants and skippers were doing well, and they rebuilt bigger. The oldest dated building still standing, Philip Kock's house, went up in 1645, in the first flush of that recovery. The suffix in the town's name says what it was for: -købing, from the Old Norse for a trading town.

Walk the lanes off the market square and the styles refuse to resolve into a single national manner. Ærø belonged to the duchy of Schleswig, and its builders borrowed from Funen to the north, from northern Germany to the south, and from Schleswig itself; the island was only formally transferred to Denmark in 1867. Most houses are a single storey, low and close to the street. The brickwork, the joinery and the ironwork are the work of local bricklayers, carpenters and smiths, each generation adapting a house that was already old rather than replacing it. Prior's House, dated to 1690, still has its original doors and Dutch tiles; Alexis Prior bought and restored it in 1917, and his name stuck. Hammerich's House, from around 1700, is now a museum kept in the character of the early 1900s.

In 2002 Ærøskøbing was awarded the Europa Nostra prize for care of cultural heritage — an award easily misread as a compliment about appearances. The unusual thing here is not the façades. It is the continuity behind them: these buildings have absorbed the housing needs of successive generations without being emptied out into a museum street. Restoration in Ærøskøbing has mostly meant keeping people inside the houses.

Two old pumps stand in the market square beside the church, and they supplied the town's water until 1952 — late enough to sit inside living memory. The church is the third to occupy that site, built in 1756–58 to replace a medieval predecessor. Coming in from the south along the main road, the first thing you see is the eight-sided Dutch gallery windmill of 1848, which ground grain until 1957 and has become the town's landmark by default. Ten minutes' walk west of the centre is Vesterstrand, where a row of small wooden beach huts is painted in colours that show no interest whatsoever in restraint.

Ærøskøbing lost its formal market-town rights in 1966; it had been the only købstad in Sønderjylland without a jurisdiction of its own. Around 917 people live here now. A modern marina has been grafted onto the historic harbour, and the Svendborg ferry still makes this the island's main gateway, which means tourism pays most of the bills. None of that has turned the place into a set. There is laundry on the lines, there are bicycles against the walls, and there are people who have lived on the same lane for forty years. The houses look the way they do because somebody is still out there painting them.