Why go
This account gives the river crossings and neighboring names historical meaning. The abbey grew on the left bank, an early village developed on the right, and Unterseen followed nearby. It helps explain why the present built-up area contains several old centers rather than one simple medieval core.
The full story
Flint objects, Bronze Age swords and Roman coins have been found near Interlaken, but they do not establish a settlement before the Middle Ages. A firmer story begins around 1133, when the Augustinian abbey was recorded on the left bank of the Aare. Its bridge brought toll income, and a village and mill grew close to it. The mill appears in a 1365 record as Amuli. Across the water, a village named Interlaken was mentioned in 1239; Unterseen developed nearby in 1279–80. The Weissenau castle and Widen market town also belonged to this earlier landscape, though both declined in the late Middle Ages. These names explain why a walk around today's Interlaken crosses layers of settlement. The old name Aarmühle still points back to the mill, while the Interlaken name originally belonged to a settlement on the other side of the river.