In the 17th century this fort was all there was to the town, but dwellings were gradually built up around it on reclaimed marshland.
In the 16th century this fort was all there was in town.
mnli hypothesis: In the 16th century this fort was all there was in town. premise: In the 17th century this fort was all there was to the town, but dwellings were gradually built up around it on reclaimed marshland.