Standalone short: how Sweden 'moved' a fortress — razing the obsolete Gamla Älvsborg and carrying its name downstream to a new sea-fort on the island, complete with a reused viking runestone. Leif + Margareta.
How do you move a fortress? [pause] It sounds impossible. But in the 1600s, Sweden actually did it — and the fortress you see here on the island is the result.
The old castle had a fatal flaw: new hills nearby looked straight down into its yard. By 1660 it was a relic. So the government condemned it — blew it up with gunpowder, and let the district cart it away as a quarry. By 1673, Gamla Älvsborg was simply gone.
But the name refused to die. They carried it two kilometres downstream, to a bare rock in the river mouth, and from 1653 they raised something new: a white star of stone straight out of the water. In 1661 it took the dead castle's name. Nya Älvsborg. Same name — new body.
And one detail says everything. Into the gate of the new tower, they set a stone far older than the fortress itself — a viking runestone. The oldest stone in the place, built into the youngest castle in Sweden. The name Älvsborg had moved, but it carried its deep roots with it.