Anglophones find it really funny that one of Sweden’s oldest towns is named Sick Tuna — spelled Sigtuna. However, -tuna has nothing to do with fish, being instead a cognate of Eng. town and Ge. Zaun. It has something to do with enclosed areas. As a reply to a question from my friend Per Vikstrand, here’s a snippet about these place names from the Migration Period chapter of my book manuscript about political geography in 1st Millennium Östergötland.
Of the place-name categories in Östergötland suggested as indicating a status above the ordinary, only one is likely to have been productive as early as the Migration Period: the -tuna names. There are eight of them, and when juxtaposed with the Migration Period’s elite indicators they do not correlate well. Only one is inside a Migration Period elite cluster, coinciding with one of the period’s three best candidates for an elite settlement site: Sättuna in Kaga. Surprisingly, the -tuna names correlate better (but overall not very strongly) with Late Roman Period elite indicators, coinciding closely at Tuna in Heda, Luntan/Luntuna in Viby and Tuna in Östra Husby. As we shall see in the next chapter, in the context of political geography the -tuna farmsteads of Östergötland as a group are mainly relevant to the Vendel Period, when four of them coincide closely with elite indicators. But regardless of their later fate, it appears that four of the eight were already important places before the end of the Migration Period. I would suggest that at least these four were named Tuna at the time, and that the name type was productive over several centuries.
In the Viking Period, all eight appear unimportant. We should note that three of them do not coincide closely with any elite indicators whatsoever from the period AD 150-1000. But five out of eight over a period of 650 years does support the long-established notion that there is something unusual about Tuna.