With Odin's departure and exile, a new governing body needed to be established to watch over the newly formed Asgardia, and all the dispart races now living with the Asgardians. The trinity of Freyja, Gaea, and Idunn together serve this purpose.
All three of them represent different aspects: Compassionate Gaea, the Mother; Imperial Freyja, the Queen; Youthful Idunn, the Maiden.
When ancient tensions with the Vanaheimr flair into outright war, the All-Mother's connections with said people lead to their imprisonment. The Asgardia people look to Volstagg of the Warriors Three for leadership. When the war falters, Volstagg attempts to free the All-Mother but they choose to stay where they are, wisely knowing that Volstagg's faith in them is much stronger then the people's.