Until the beginning of the 20th century, however, the general opinion was that a good many Finland-Swedes were descended from Finns. An indication that this was the case was seen in the fact that a number of Finland-Swedish family names are derived from Finnish place names, e.g. Ascholin from the parish of Askola or Frosterus from a homestead called Pakkala (pakkanen is the Finnish word for frost). It was, however, a prevailing custom among Swedish clergymen, burghers and freeholders to create family names out of place names, and most place names in Finland were Finnish.

The Finnish historian Väinö Voionmaa (1869-1947, né Wallin) has shown that the custom of using homestead names as family names was established already in the 14th century. The Christian names of this period fall into three categories: Biblical names (in their Swedish form), Nordic (pagan) names and Finnish names. The first type was much in vogue in all places, while the Finnish names occurred mainly in eastern Finland, but were extremely rare in western Finland. Nordic names like Sigvard, Hemming and Gudmund would hardly have been used by Finns who had access to a great number of pure Finnish names as A.V. Forsman (1856-1929, from 1906 Koskimies) demonstrated in 1891. The person who turns up in the documents as Sigvard Torkilson Kandala would therefore have been Swedish, despite his Finnish surname, which was most likely the name of his homestead (Voionmaa 13-24). There are many persons like Sigvard in the old records.

As a consequence, the old family names cannot be taken as indicators of the language of the bearer. Jakob Bengtsson Ilkka, the leader of the peasants' rebellion in 1596-97 (the "War of Clubs"), may well have been a Finland-Swede in spite of his Finnish surname. The Christian names, given by the parents, give better clues to the ethnic affiliation. There is a snag, however. Most Finnish reference books enter all historic Finlanders under the Finnish forms of their first (biblical, classical) names, i.e. in many cases simply translations of the names given at christening. Thus Jakob Ilkka is entered as Jaakko Ilkka, Viktor Peltonen (known as "Johannes Linnankoski") as Vihtori, Zachris Topelius as Sakari, Johan Ludvig Runeberg as Juhana, and so on. We can be fairly sure that persons called Aimo, Ilmari, Kalervo, Kauko, Veli, Veikko or by any other original Finnish name, were entered under these names in the parish register. Their parents would in all probability have been Finns. Persons appearing as Antti, Jaakko, Mikko, Pekka or Sakari require, however, a careful research to establish the registered form of their Christian names. If this turns out to have been Anders, Jakob etc. it simply means the bearer may have been Swedish. He could, however, also have been a Finn, since the Finnish forms of biblical names were right up to the 19th century regarded almost as nicknames and thus not always approved as baptismal names for anybody. Consequently, Jakob Ilkka could also have been a Finn, despite his Swedish baptismal name. Most probably he was a Swede, however, since he was born on a cavalry freehold (rusthåll), to a father who was also a lay assessor (nämndeman). Jakob himself was a sheriff (länsman) and he is known to have married a Swedish woman. Jakob's son Josef became mayor of the town Nykarleby where only Swedish was spoken at the time. (Ylikangas, p. 125-127.) As a leader of both Swedish and Finnish peasants, he was probably bilingual.

Because of these complicated circumstances and the absence of information about the genetic facts, it was possible for scholars like Henrik Porthan (1739-1804) and Gabriel Rein (1800-67) to believe that Finland had once been populated exclusively by Finns and that the Finland-Swedes were descended partly from these Finns and partly from rather late "conquerors" from Sweden. Thus many a Finland-Swede looked at Snellman's program for "going Finnish" as a return to their ancestral ethnicity. The result is that a reference book such as Uppslagsverket Finland enters many a distinguished person with a Finnish surname, but with an original Swedish family name added in brackets. Among the about 200 cases we note e.g. the archaeologist Julius Ailio (né Ax), Lönnrot's biographer Aarne Anttila (né Andelin), the actor-producer Kosti Elo (né Ekman), the previously mentioned ethnosociologist Uno Harva (né Holmberg), the actor-producer Vilho Ilmari (né Sundberg), the composer Ernst Linko (né Lindroth), the politician Edwin Linkomies (né Flink), and the meteorologist Vilho Väisälä (né Veisell), to mention just a few who were known abroad as well as at home. Almost a fifth of all Finnish surnames in the reference book are replacements of former Swedish names.

Professor Porthan actually believed (or pretended to believe) that the clergy and most of the burghers and persons of rank had spoken Finnish with each other in the beginning of the 18th century. In connection with this assertion he also noted that Baron Claes Fleming (1533-97) had spoken such a bad Swedish that his fellow councillors had great difficulty in understanding him. With this statement Porthan gave rise to the long-lasting illusion that Baron Fleming had been a Finn. (Fleming's mother and wife were Swedish noblewomen and Swedish was the only language spoken by the people living on the Fleming domains in southern Finland. The Fleming family hardly knew any Finnish at all, but their dialect may well have been regarded as boorish by refined Stockholmers.)

Incidentally, the idea that cultivated people should have spoken Finnish with each other about the year 1700 is untenable, because Finnish at that time lacked all the words needed to give the conversation an educated content.

It is rather absurd and almost ludicrous to read the lectures of Professor Gabriel Rein at the Helsinki University (prepared in 1834, printed in 1870). In front of an audience consisting of at least 90 percent Finland-Swede students, Professor Rein (1800-1867, with a thoroughly Finland-Swede pedigree) told his students e.g. that "later, when the Swedes had got to know our country they took over the name Lapp used by our ancestors for the nomads in Finland". Rein apparently took it for granted that his Swedish audience regarded "the Swedes" as an alien people separated from "our ancestors".

In spite of all this false belief of the past centuries, recent research leaves no doubt: the Finland-Swedes as a group are not descended from the Finns although they are closely related. This kinship depends, however, on the Finns having a substantial portion of Swedish ancestry. As patriotic Swedes and after 1809 as patriotic Finlanders many Finland-Swedes have done notable achievements in various fields. They are ethnically distinguishable from the Finns and--to a much lesser degree--also from the Swedes of Sweden. By retaining their language they have powerfully strengthened Finland's attachment to the Scandinavian countries and thereby to the Western World. Without the Finland-Swedes, Finland would not have been anything like what it is to-day.