She married Gisulf II of Friuli, and became the mother of the sons Tasso, Kakko, Radoald and Grimoald, and the daughters Appa and Geila (or Gaila), married to the King of the Alemanni (uncertain) and the Prince of the Bavarians, probably Garibald II of Bavaria.
In 611, the Duchy of Friuli was invaded by the Pannonian Avars under their king Bayan II, who is referred to as "Cacan" in the traditional story of Romilda.
Gisulf II died on the battlefield, and the Avars besieged the main capital Friuli, which was defended by Romilda, who had taken command as regent.
However, when Romilda surrendered the city, Friuli was pillaged by Bayan II, who broke his word.
Romilda has been given a very bad reputation in history because of Paul the Deacon, who in his chronicle from the following century claimed, that she made the offer of marriage to Bayan II out of personal attraction, and betrayed her city out of sexual lust.