Stiernhielm's most famous poetic work is the first poem in the Musæ Suethizantes, the Hercules composed in hexameter, with names and fables borrowed from the ancient Greeks.
The very following year he traveled again to Germany, as a tutor for a young Gyllenhielm, and also visited Italy, France, the Netherlands and England.
In 1626 he was called by Bishop Johannes Rudbeckius to be a lecturer at the high school in Västerås, and shortly afterwards he was appointed by King Gustavus Adolphus as "reading master for the Riddarhuset" in the then Collegium illustre.
He was bedridden for a long time, and suffered such permanent pain from the injury that after recovery he was forced to write with his left hand.
He stayed several years in the capital, attracted attention for his talent and knowledge, and also gained high favor with Queen Kristina for his poems.
[2] In 1648, he was appointed vice president of Tartu's court of appeals, but had barely taken up this position before he was recalled to Stockholm to become national antiquary.
But when this county was lost again in 1660, Stiernhjelm was again without work, until in 1661 he was called to the council of war and the following year to a member of the Reduktionskollegium, a position he however declined.
Stiernhielm tried to prove that Gothic, which he equated with Old Norse was the origin of all languages, and that the Nordic countries were vagina gentium, the human birthplace.
The allegory, known as Hercules at the crossroads, can be traced back to the Athenian sophist Prodicus of Ceos, as preserved in Xenophon.