The Hùng temple complex marks the site where, according to Vietnamese legend, the fairy Âu Cơ, wife of King Lạc Long Quân, gave birth to a pouch containing 100 eggs which hatched to produce 50 boys and 50 girls. When husband and wife separated in order to populate the land and propagate the race, half of the children followed their mother into the mountainous districts and the other half followed their father into the lowlands, thus giving rise to the upland ethnic minority people and the lowland Việts respectively. Archaeological evidence links the site with the historic Hùng kingdom of Văn Lang, which was based in the Việt Trì area from the start of the Bronze Age and flourished until the 3rd century BCE. Finds dating from several different eras of Hùng hegemony, including Sơn Vi (paleolithic), Phùng Nguyên (neolithic) and Đông Sơn (1st millennium BCE), have been found in the surrounding area, and these may be viewed in the Hùng Vương Museum. The temple complex itself comprises lower, middle and upper temples. The Lower Temple was built on the site where Âu Cơ is supposed to have given birth; it was originally constructed many centuries ago by local villagers and repaired during the Lê era (18th century). The Middle Temple, originally constructed as a place for kings to rest and discuss affairs of state during the late Trần era (14th century), was destroyed during the 15th century and has been rebuilt over the last 200 years. Situated at the top of the hill is the Oath Stone Pillar on which the 18th Hùng king, Thục Phán, swore to defend the country from its enemies. Close by is the Upper Temple, a 15th-century reconstruction of the original temple where the Hùng kings would pray to the gods for the peace and prosperity of the nation. The complex is particularly busy during the Hùng Temple Festival, a major event in the regional calendar which takes place in the third lunar month. In 2004 provincial authorities approved a major project to restore and develop this important site, scheduled for completion by 2015.