The Frisian (also written as Friesian) flag has developed at the end of the nineteenth century. The inspiration comes from a weapon garment. The garment had a blue background and three sloping silver colored broad lines. On these silver lines seven red leaves of waterlilies (pompeblêden) where laying.
Prove has been found that the Frisian weapon garment hail from scandinavian origin. In the song of Gudrun from the 11th century even there is spoken of a flag with waterlilies leaves.
In 1957 the flag with the waterlilie leaves became the official flag of Friesland.
Declaration of the flag is as follows:

The three white stripes are for the country regions named: Oostergo, Westergo and Zevenwouden. The blue stripes for the Frisian rivers.
The seven leaves are for the seven old Frisian sealands, as they existed between the eight and fourteenth century.
- Frisia between Reker and Vlie ( Western-Friesland, where the provinz North-Holland lies now)
- Frisia between Vlie and Middelzee ( Westergo, the western part of Friesland)
- Frisia between Middelzee and Lauwers ( Oostergo, the eastern part of Friesland )
- Zevenwouden ( the southern part of Friesland )
- Frisia between Lauwers and Eems ( Ommelanden, lies in the current provinz of Groningen )
- Frisia between Eems and Jade ( Ostfriesland , lies in Germany )
- Frisia between Jade and Weser ( lies in Germany )