From A Wiki of Ice and Fire
|Alias||Daenys the Dreamer|
|Title||Lady of Dragonstone|
|Spouse||Gaemon the Glorious|
|Book(s)||The World of Ice and Fire|
When Daenys was still a maiden  she had visions (and a powerful prophetic dream that Valyria would be destroyed,) that moved her father Aenar to relocate his family to Dragonstone, twelve years before the Doom of Valyria.  She married her brother Gaemon the Glorious. Their children were Aegon and Elaena Targaryen.
Signs and Portents
By the time of the War of the Five Kings, it is believed visions written down by the maiden daughter of Aenar Targaryen before the Doom came to Valyria were in a book called Signs and Portents, that is now lost. Archmaester Marwyn claimed he found three pages from it in his Book of Lost Books.