Medieval Bremen sorted itself by elevation, and the sorting was social as much as geological. The wealthy merchants took the Obernstraße, the upper street, along the crest of an old dune, or the Langenstraße running beside the Balge, the arm of the Weser that served as the city's first harbour. What was left was the low ground: a scrap of island between the Balge and the river, where from about the tenth century fishermen threw up thatched cottages and lived with the consequences. High water came through regularly in those first centuries. This was the poor corner of a Hanseatic city that was not otherwise poor, and it stayed the poor corner for the next nine hundred years - which turns out to be the single most important fact about it.

Small does not mean unimportant. Bremen's first ferry crossing worked from here, and around 1240 the first bridge over the Weser was thrown across near this bank, which for a river city is the moment everything changes. Fragments of the period are still embedded in the fabric: an old stretch of wall and part of a round tower raised around 1200 stand near the lane called Marterburg. In the thirteenth century Franciscan friars settled in the quarter and began the church of St. John, brick, aisled and famously towerless, which is still in use and still listed. The friars have a modern echo - a small Bridgettine convent, the Birgittenkloster, was founded in the Schnoor in October 2002, which makes it one of the newest religious houses in Germany sitting inside one of the oldest streets.

The oldest surviving houses go back to around 1400; most of what stands is seventeenth and eighteenth century. By the nineteenth, the lanes were hopeless for traffic and the quarter had become one of the poorest parts of Bremen, which meant that renovation was simply out of reach. Nobody widened the streets. Nobody replaced the gables with something modern. Then came the war, and the Schnoor took only slight damage while the city around it was flattened - so slight that after 1945 the owners of these undamaged houses were liable for the Lastenausgleich, the levy that redistributed wealth from the spared toward the bombed out. They had escaped the RAF and were taxed for it. By the mid-1950s the houses were in a pitiable state and looked like the next thing to come down.

In 1959 the Bremen Senate chose to rebuild the quarter rather than clear it, inviting house owners to restore their wrecks with money from the state. Set that against what was happening everywhere else. Across Germany and much of Europe into the late 1970s, the standard treatment for a decayed medieval district was demolition and a road; Bremen went the other way two decades before the argument was settled. The Venice Charter for the Conservation and Restoration of Monuments and Sites in 1964 changed the climate, and in 1973 the Schnoor was designated a historic district under the State Monument Authority. A planning decision in 1981 went further and capped the number of bars and restaurants at fourteen, on the reasoning that a quarter full of tourists and no residents is a stage set.

Names are painted on the houses because the houses are old enough to have them. The Concordenhaus dates from 1630, the Amtsfischerhaus from 1759, and the Schifferhaus on Stavendamm is the one preserved closest to its original state. There is a Landherrnamt of 1856, built for the officials who administered the state of Bremen, and an old tea house on the lane called Hinter der Holzpforte, and a Katzencafé whose sign is the most photographed thing in the neighbourhood. Craftspeople and small dealers work out of ground floors that were built for fishing families. It is unquestionably a tourist quarter now, and the crowds thin the moment it rains. Stand in one of the passages then, with the gables closing overhead and water running off four hundred years of brick, and the fishermen's island is not hard to find.