The next period of Lithuanian mythology started in the 15th century, and lasted till approximately the middle of the 17th century. The myths of this period are mostly heroic, concerning the founding of the state of Lithuania. Perhaps two the best known stories are those of the dream of the Grand Duke Gediminas and the founding of Vilnius, the capital of Lithuania, and of Šventaragis' Valley, which also concerns the history of Vilnius. Many stories of this kind reflect actual historical events. Already by the 16th century, there existed a non-unified pantheon; data from different sources did not correspond one with another, and local spirits, especially those of the economic field, became mixed up with more general gods and ascended to the level of gods.