Born around 980, Hemma lost her parents at an early age, and was adopted by Emperor Heinrich II and his wife Kunigunde, who took her to the imperial court in Bamberg. As Countess von Friesach-Zeltschach, she married Count Wilhelm von der Sann, thus becoming one of the most powerful women in Carinthia.
Her high rank did not save her from bitter blows of fate, losing her children while still young and her husband, murdered by the rebel Duke of Carinthia Adalbero von Eppstein in 1036 for having remained loyal to the Emperor. As a widow, she had sole control over the rich inheritance of two mighty families with possessions in Carinthia, Styria and Carnia. With the agreement of her relatives, she applied the larger part of this inheritance to the foundation of two monasteries and a number of churches, and to the welfare of the poor. In 1036, Benedictine nuns from Nonnberg in Salzburg took up residence in the new convent in Gurk, which Hemma also entered as a lay sister. The founder died aged around 65 on June 27, 1045, and was buried in the convent cemetery.
The Gurk convent was not to survive for long. Archbishop Gebhard von Salzburg abolished it in 1072, founded the Bishopric of Gurk and transferred to the latter the estates of Hemma's convent. He was also responsible for the building of Gurk Cathedral, and used St. Hemma's estate to construct the monastery at Admont. The memory of the Countess of Friesach fell into oblivion, but in their struggle for independence from Salzburg, the bishop and cathedral chapter recalled their own founder, and in 1174 her bones were ceremoniously transferred to the new 100-column crypt of Gurk Cathedral, one of the most beautiful Romanesque churches in Austria, and placed to rest.
The oldest portrait of the saint is to be found in a fresco in Gurk Cathedral dating from 1220. Hemma is almost always portrayed as an elegant lady with a strikingly large bonnet, holding a model of a church in one hand and distributing alms. The memory of a just ruler gradually developed into the legend of the fair wage. Hemma, whose wont it was to pay her workers herself, allowed anyone who complained about their low wage to put their hand into the money bag themselves. But no matter how greedily they grabbed, they would only get the wage intended for them. She would be sitting on a stone of serpentine, which is now on display in the crypt under the name of the "Hemma Stone", and is sat on by women hoping for children. Saint Hemma is also invoked for a happy childbirth and above all for eye complaints. The traditional blessing of the eyes is documented as far back as the 15th century. She was only canonised on January 5 1938 by Pope Pius XI. The anniversary of the death of the patron saint of Carinthia is celebrated on June 27, St. Hemma's Day.