The Nuttall Encyclopedia
In the Norse mythology the wife of Balder, the sun-god; distinguished for her conjugal fidelity, threw herself on the funeral pyre of her husband, and descended to the shades along with him; when the pair were entreated to return, he sent his ring to Odin and she her thimble to Frigga.
Wood, James, ed. Entry for 'Nanna'. The Nuttall Encyclopedia. https://www.studylight.org/encyclopedias/eng/nut/n/nanna.html. Frederick Warne & Co Ltd. London. 1900.