Flag families are sets of national flags with design similarities based on a shared history, culture or inspiration. Families do not include flags with coincidental similarities. Flags may be in multiple flag families. Only twelve current national flags existed before the 19th century, when large-scale flag use began. Seven of these flags (Denmark, France, the Netherlands, Russia, Turkey, the United Kingdom, and the United States of America) are the inspiration for more than 130 current national flags and ensigns.