In 1946, just a year after the formation of the socialist regime in Vietnam, then President Ho Chi Minh signed a decree to allow civil servants a holiday on the third day of the third lunar month.

However, the decree meant little as the nation stared down the barrel of what would prove to be decades of warfare. Not until 1994, when the Labour Code came up for discussion by the National Assembly, was the holiday notion tabled again.

Today, more than 13 million labourers are guaranteed at least nine holidays each year, including four days at Tet (determined by the lunar calendar), western New Year's Day( Jan 1), Liberation Day (April 30), International Labour Day (May 1), and National Day (September 2).

Their capital was Phong Chau, a place that historical records and legends combined place squarely in Viet Tri City, around 70km West of Hanoi. The location was strategically important, hemmed in by steep mountains and the confluences of the Red, Da and Lo Rivers.

In their capital, the kings built stately palaces and administrative buildings, which are today being excavated by archaeologists, primarily around Tho Son ward in Viet Tri. The digs have uncovered many tombs, filled with jewellery, weapons and musical instruments made of copper and iron.

Today, there are more than 1,400 places of worship for the Hung Kings. In Viet Tri alone, pilgrims may visit holy sites such as Den Tien (the Fairy Temple), Hung Vuong To Mieu (the Forbidden . Temple), and Thien Co Mieu (Thien Co Temple).

For the agnostic, near to Thien Co lies a rice field that is said to be associated with the legend of square glutinous rice cakes.

The primary place of worship is the Hung Temple complex, which is upon Nghia Linh Mountain in Hy Cuong Commune, Lam Thao district, 10km West of Viet Tri. For generations, this temple has been not only a spiritual centre, but also a symbol of national unity.

The complex includes four main temples and a mausoleum, which is said to be the tomb of the sixth Hung King. In 2005, a temple to worship "Mother of the Nation" Au Co was added to the complex, and this year, construction began on a temple to worship "Father of the Nation" Lac Long Quan. To gain further insight into life during the period, the Hung Dynasty museum next to the Main Gate provides interesting information and displays.

This year's celebrations run April 16-26, or from the sixth to the tenth days of the third lunar month.

Celebrations will be held at both the temple and in Viet Tri City, with festivities climaxing on April 26 with a spiritual ceremony within temple complex, and palanquin parades in the surrounding villages. From April 22, a fair, will be held, with local handicrafts up for sale, as well as performances of folk music and games.