The surprising establishment of an archdiocese led to an unprecedented building boom in Hammaburg. Even though the castle itself laid waste since the Viking attack in 845, people still settled on the former castle area and its surroundings. In the year 900 a new, and even more powerful, fortification with a moat and rampart was built, the Hammaburg III. At the same time people began to backfill the riverbank below Hammaburg. The shore was fortified with staggered wooden barriers and wooden embankments. Parallel to the shore numerous small wattle houses and log cabins were built. For the first time in history, the settlement included the opposite shore of Reichenbach Island (Reichenbachinsel), where a shore market came to life next to tightly positioned wattle and daub houses. The oldest port of Hamburg took shape on both sides of the shore.