This article concerns insubordination, that is, the use of clause types which are ordinarily considered subordinate but occur without main clauses. We study the use of insubordinate relative clauses (RCs) in Finnish with data from two corpora, the Arkisyn corpus of contemporary conversation and the Agricola corpus from the 16th century. Our main findings are that the construction is put to very similar uses in the two corpora, but that it is more common in the newer corpus. We show that insubordination of RCs existed along with subordination already in the earliest records of Finnish language use. Thus, insubordination of RCs is not a more recent development than their use as subordinate clauses. We conclude that the more frequent use in the newer data is likely not a result of a process of grammaticalization that would have occurred since the 16th century.