Old Welsh (Welsh: Hen Gymraeg) is the stage of the Welsh language from about 800 AD until the early 12th century when it developed into Middle Welsh. The preceding period, from the time Welsh became distinct from Common Brittonic around 550, has been called "Primitive" or "Archaic Welsh".
Hafren (or Sabre, Sabren, or Sabrina; Welsh: Hafren; Old Welsh: Habren) is a legendary British princess who was drowned in the River Severn by her repudiated stepmother Gwendolen. The legend appears in Geoffrey of Monmouth's pseudohistorical chronicle Historia Regum Britanniae (c. 1136). According to Geoffrey, Hafren is the eponym of the Severn, which bears one of Britain's most ancient river names (recorded as early as the 2nd century in the Latinized form Sabrina).
Segontium (Old Welsh: Cair Segeint) is a Roman fort on the outskirts of Caernarfon in Gwynedd, North Wales.
The Book of Aneirin (Welsh: Llyfr Aneirin) is a late 13th century Welsh manuscript containing Old and Middle Welsh poetry attributed to the late 6th century Northern Brythonic poet, Aneirin, who is believed to have lived in present-day Scotland.
The manuscript is kept at the National Library of Wales, Aberystwyth. It is made of parchment and was written in Wales around 1265, probably in a monastery, but is probably a copy of a lost 9th century original. The text of the manuscript is rendered in a proto-gothic hand. There is minimal decoration, consisting of only of a few colored Lombardic Capitals. Paragraphs are broken by similarly colored pilcrows and where the text breaks before the right margin, simple illustrated linear termini are provided.