Warns is a village in the northern Netherlands. It is located in the municipality of Súdwest-Fryslân, Friesland. It had a population of around 720 in January 2017. Warns is best known for the Battle of Warns. In 1345, count William IV of Holland tried to invade Friesland. A battle took place at the Roode Klif, a nine metre high clay ridge, on the former Z…Warns is a village in the northern Netherlands. It is located in the municipality of Súdwest-Fryslân, Friesland. It had a population of around 720 in January 2017. Warns is best known for the Battle of Warns. In 1345, count William IV of Holland tried to invade Friesland. A battle took place at the Roode Klif, a nine metre high clay ridge, on the former Zuiderzee where the invasion was stopped. Almost the entire army of Holland including count William were killed during the battle.