Yes, a less ambiguous way of phrasing it might be "coins from cities in what is now Sweden, Britain, and Germany".
People may be wondering about metal detecting laws in Finland, and whether the finder can keep the coins. The answer is, ultimately, no. In Finland, any buried artifact more than 100 years old belongs to the State. Finders who comply with the law and report their finds promptly are rewarded; the minimum value of the reward is the scrap metal value plus 25%, with higher rewards given for historical significance, but the reward is not necessarily proportional to the "true market value" of the items. Finders are only allowed to keep their finds if the State museums already have so many of similar items they don't want it, so state ownership is relinquished.
These coins (and the other artifacts) will almost certainly remain in State ownership, in a museum. The coins were found less than a month ago so they are probably still being cleaned and identified.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis