The Flag of the province of Friesland or Frisian flag is the official flag of the Dutch province of Friesland.
It consists of four blue and three white diagonal stripes; in the white stripes are a total of seven red pompeblêden, leaves of the yellow water-lily, that may remind one of hearts, but according the official instructions "should not be heart-shaped". The jerseys of the football club SC Heerenveen and the Blauhúster Dakkapel are modeled after this flag.
The seven red seeblatts (or pompeblêden, as they are called in Frisian) are a reference to the Frisian "sea countries" in the Middle Ages: independent regions along the coast from Alkmaar to the Weser who were allied against the Vikings. There were never precisely seven distinct regions, but the number seven probably has the connotation "many." Some sources hold, however, that there have been seven Frisian lands: West Friesland, Westergoa, Eastergoa, Hunsingo, Fivelingo, Emsingo, and Jeverland.
The pompeblêden are used in other related flags such as the flag of the Ommelanden in neighbouring Groningen Province, a historically Frisian area, and for a proposed pan-Frisia flag put forth by the Groep fan Auwerk.
In the 13th century a flag with pompeblêdden is described in an epic poem. Evidence for this lies within verses of the Gudrunlied. Round 1200 Scandinavian coats of arms reveal many traces of water-lilies and hearts, found often in combination with images of lions.
15th century books on heraldry show that two armorial bearings were derived from the early ones: a coat of arms showing lions and seven pompeblêdden (water lillies) transformed into billets, the other being the arms with the seven now known lilies on stripes.
The current design was officially approved in 1897 and was first used by the provincial government in 1927.