The earliest mention of Estonian singing dates back to Saxo Grammaticus ''Gesta Danorum'' (ca. 1179). Saxo speaks of Estonian warriors who sang at night while waiting for a battle. The older folk songs are also referred to as ''regilaulud'', songs in the traditional ''regivärss'' poetic metre shared by all Baltic Finns. Runic singing was widespread among Estonians until the 18th century, when rhythmic folk songs began to replace them.