A short note about the ''Dani'' in ''Getica'' by the historian Jordanes is believed to be an early mention of the Danes, one of the ethnic groups from whom modern Danes are descended. The Danevirke defence structures were built in phases from the 3rd century forward and the sheer size of the construction efforts in AD 737 are attributed to the emergence of a Danish king. A new runic alphabet was first used around the same time and Ribe, the oldest town of Denmark, was founded about AD 700.