Louis was born at Creuzburg Castle, the second son of Landgrave Hermann I of Thuringia, from his marriage with Sophia,[1] a daughter of the Wittelsbach duke Otto I of Bavaria.

[2] During the German throne quarrel between the Hohenstaufen ruler Philip of Swabia and his Welf rival Otto IV, his father switched sides several times and tried to expand his own influence by betrothing his eldest son Hermann to the Hungarian princess Elizabeth, daughter of King Andrew II.

At Wartburg Castle in 1220 at age twenty, Louis married 14-year-old Elizabeth of Hungary,[4] with whom he had three children: Hermann II, Sophie, and Gertrude, later abbess at Altenberg.

Like his father, Louis was in close contact with the Hohenstaufen emperor Frederick II, who appointed him a Marshal of the Holy Roman Empire and confirmed his rights in the Margraviate of Meissen.

In August 1227 Louis traversed the mountains between Thuringia and Upper Franconia, through the duchies of Swabia and Bavaria, crossing the Tyrolian Alps.

After his death, Elizabeth left the court, made arrangements for the care of her children, and in 1228, renounced the world, becoming a tertiary of St. Francis of Assisi.