The Prose Edda 1.26

"One is called Bragi: he is renowned for wisdom, and most of all for fluency of speech and skill with words. He knows most of skaldship, and after him skaldship is called bragr, and from his name that one is called bragr-man or -woman, who possesses eloquence surpassing others, of women or of men. His wife is Idunn: she guards in her chest of ash those apples which the gods must taste whensoever they grow old; and then they all become young, and so it shall be even unto the Weird of the Gods." Then said Gangleri: "A very great thing, methinks, the gods entrust to the watchfulness and good faith of Idunn." Then said Hárr, laughing loudly: "'T was near being desperate once; I may be able to tell thee of it, but now thou shalt first hear more of the names of the Æsir.