An ol'Skool Finnish name...Unique name, means unique person! rep-pre-sent...In the beginning God create Seija...ha! no serious, some dude/or dudette found name "Seia" in a book on religions of the world. Seia was ancient Roman god of new crop. They combined that with an old Finnish word "seijas" (serene, calm, clear, tranquil) and got Seija. .
The first recorded Seija was Ester Seija Karilas who was born in 1917 (that'd make the name the same age as the independence of Finland...) The Karilas' had a family friend who wrote a novel in 1924 called "The Story of Seija-girl" which made the name quite popular