). His father, Christian Castren,
parish minister at Rovaniemi, died in 1825; and Matthias passed under
the protection of his uncle, Mathias Castren, the kindly and learned
incumbent of Kemi. At the age of twelve he was sent to school at
Uleaborg, and there he helped to maintain himself by teaching the
younger children. On his removal to the Alexander University at
Helsingfors in 1830, he first devoted himself to Greek and Hebrew with
the intention of entering the church; but his interest was soon excited
by the language of his native country, and he even began before his
course was completed to lay the foundations of a work on Finnish
mythology. The necessity of personal explorations among the still
unwritten languages of cognate tribes soon made itself evident; and in
1838 he joined a medical fellow-student, Dr. Ehrstrom, in a journey
through Lapland. In the following year he travelled in Russian Karelia
at the expense of the Literary Society of Finland; and in 1841 he
undertook, in company with Dr Elias Lonnrot, the great Finnish
philologist, a third journey, which ultimately extended beyond the Ural
as far as Obdorsk, and occupied a period of three years. Before starting
on this last expedition he had published a translation into Swedish of
the Finnish epic of _Kalevala_; and on his return he gave to the world
his _Elementa grammatices Syrjaenae_ and _Elementa grammatices
Tscheremissae_, 1844. No sooner had he recovered from the illness which
his last journey had occasioned than he set out, under the auspices of
the Academy of St Petersburg and the Helsingfors University, on an
exploration of the whole government of Siberia, which resulted in a vast
addition to previous knowledge, but seriously affected the health of the
adventurous investigator. The first-fruits of his collections were
published at St Petersburg in 1849 in the form of a _Versuch einer
ostjakischen Sprachlehre_. In 1850 he published a treatise _De affixis
personalibus linguarum Altaicarum_, and was appointed professor at
Helsingfors of the new chair of Finnish language and literature. The
following year saw him raised to the rank of chancellor of the
university; and he was busily engaged in what he regarded as his
principal work, a Samoyedic grammar, when he died on the 7th of May
1853.

Five volumes of his collected works appeared from 1852 to 1858,
containing respectively--(1) _Reseminnen fran aren_ 1838-1844; (2)
_Reseberaitelser och bref