Given that Finland for centuries has contained far more people named Helenius...
Given that Finland for centuries has contained far more people named Helenius that Helinijus, why is it that the country today contains only 132 people carrying the surname Helen (a shortened version of Helenius) but 3,383 carrying the surname Helin (a shortened version of Helinius)? Or in other words, why has Helenius evolved into Helin rather than Helen?
During the 16th and 17th century, many academic Finns added “-ius” to their name so that their name would look like more Latin and therefore more “elegant”. The Historical Church Register (http://hiski.genealogia.fi/hiski?fi) tells us that there were a lot of persons named Helenius but only two persons named Helinius, so I think “Helen” (or the common form “Helén”) wasn’t formed by shortening “Helenius”. Of course, “Helin” and “Helén” were also used alongside with “Helenius”; everyone didn’t change their names to the more “elegant” form. During the 19th and 20th century, many Finns shortened their names removing “-ius” from their name or even replaced their Swedish names with Finnish names, but some retained their “ius” name.
The surnames “Helin”, “Helen” and “Helenius” are probably based on the same the Swedish word “häll” (‘a block of stone’), but there may be other etymologies, too.