The Iron Age Sarmatians (Latin Sarmatæ or Sauromatæ, Sanskrit Sakas Greek Σαρμάται, Σαυρομάται) were an Iranian people in Classical Antiquity, flourishing from about the 5th century BC to the 4th century AD.

Their territory was known as Sarmatia to Greco-Roman ethnographers, corresponding to the western part of greater Scythia (modern Southern Russia, Ukraine, and the eastern Balkans). At their greatest reported extent, around 100 BC, these tribes ranged from the Vistula River to the mouth of the Danube and eastward to the Volga, bordering the shores of the Black and Caspian seas as well as the Caucasus to the south.

The Sarmatians declined in the 4th century with the incursions connected to the Migration period (Huns, Goths). The descendants of the Sarmatians became known as the Alans during the Early Middle Ages, and ultimately gave rise to the modern Ossetic ethnic group.

Sarmatae is in origin probably just one of several tribal names of the Sarmatians which came to be applied to the entire group as an exonym in Greco-Roman ethnography. Strabo in the 1st century names as the main tribes of the Sarmatians the Iazyges, the Roxolani, the Aorsi and the Siraces.

King Arthur is a legendary British leader of the late 5th and early 6th centuries, who, according to medieval histories and romances, led the defence of Britain against Saxon invaders in the early 6th century. The details of Arthur's story are mainly composed of folklore and literary invention, and his historical existence is debated and disputed by modern historians. The sparse historical background of Arthur is gleaned from various sources, including the Annales Cambriae, the Historia Brittonum, and the writings of Gildas. Arthur's name also occurs in early poetic sources such as Y Gododdin.

The legendary Arthur developed as a figure of international interest largely through the popularity of Geoffrey of Monmouth's fanciful and imaginative 12th-century Historia Regum Britanniae (History of the Kings of Britain). Some Welsh and Breton tales and poems relating the story of Arthur date from earlier than this work; in these works, Arthur appears either as a great warrior defending Britain from human and supernatural enemies or as a magical figure of folklore, sometimes associated with the Welsh Otherworld, Annwn. How much of Geoffrey's Historia (completed in 1138) was adapted from such earlier sources, rather than invented by Geoffrey himself, is unknown.