Disa is the heroine of a Swedish legendary saga, which was documented by Olaus Magnus, in 1555. It is believed to be from the Middle Ages, but includes Old Norse themes.
It was elaborated by Johannes Messenius in his drama Disa, which was the first historic play in the Swedish language, and was played at the Disting of 1611. It was also presented in an exaggerated version by Olaus Rudbeck in his Atlantica (1685–89)
In a time when the god-king Freyr (or king Sigtrud) ruled in Sweden, there was a famine. The long peace during Freyr's reign had greatly increased Sweden's population until the lands could no longer support it sufficiently.
The king and the chieftains decided that the population had to be culled by killing all the elderly, sickly and handicapped, and by sacrificing them to Odin. However, Disa, the daughter of the chieftain Sigsten of Venngarn in Uppland, was upset by this cruel solution. She talked mockingly to the king and chieftains about their wisdom and claimed to have wiser words of advice.
In order to test her wits, Freyr asked her to visit him, but she could not do so by foot, by horse, in a wagon, nor in a boat. She could not visit him either dressed or undressed. The time must not be within a year nor within a month, and neither during daytime nor nighttime, and neither when the moon was waxing nor waning. (Compare the story of Kráka, who was issued a similar test by her future husband.)
She passed the test by harnessing two young men to a sled. By the sled, she had a billygoat and she had one leg over the goat and the other leg in the sled. For clothes she had a net, and she arrived during full moon at dusk to the king on the third day after Yule, all months had 30 days and the last month was to an end and also the year.