Elias Lonnrot was a country physician, not a court poet, and the Kalevala he is credited with is a compilation rather than an original composition in the ordinary sense. Beginning in the 1830s, Lonnrot made a series of collecting journeys through rural Karelia, then still home to active oral singers, recording folk poetry performed in the distinctive trochaic tetrameter now called the Kalevala metre, a verse form built on syllable stress patterns and heavy use of parallelism, in which a line's idea is immediately restated in different words.
Lonnrot arranged and edited this collected material into a continuous narrative, publishing a first version, the Old Kalevala, in 1835, and a substantially expanded New Kalevala, the version most commonly read today, in 1849. Because Lonnrot worked from many singers' separate performances rather than from one fixed source text, questions about how much of the finished epic's narrative shape is his own editorial contribution, rather than a pre-existing whole he merely wrote down, have been debated by folklorists since the nineteenth century and remain part of how the work is studied rather than a settled footnote.