The city originally grew up around a medieval hilltop castle (long since demolished), and later became one of the county’s five stannary towns, where tin was assayed and stamped before export. Surprisingly, it was also once a port, but the unexpected silting up of the river meant that all the maritime trade shifted over to Falmouth, and the town’s quays (including Lemon Quay and Back Quay, both near the Hall for Cornwall) now exist only in name.