Wikipedia
Old Welsh is the label attached to 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".
Many poems and some prose have been preserved from this period, although some are in later manuscripts, for example the text of y Gododdin. The oldest surviving text entirely in Old Welsh is probably that on a gravestone now in Tywyn church, thought to date from the 7th century. A text in the Lichfield Gospels called the Surrexit Memorandum is thought to have been written in the early 8th century but may be a copy of a text from the 6th or 7th centuries.
Usage examples of "old welsh".
Horses in these parts can very easily be stolen, its an old Welsh game, as I know.
Intent, fascinated, Bran began to pick out the plaintive notes of an old Welsh lullaby, elaborating it gradually, filling it out, as he gained confidence in the feel of the strings under his one hand.
So one day he went to the old Welsh basket maker who served us, and bade him make a great basket after his own pattern, the like of which the old man had never so much as thought of.
He used to quote an old Welsh saying he was fond of: 'Let all the blood be on the front of you.
The sheriffs sergeant came, and listened to Madogs tale, with only a momentary narrowing of eyes at the fleeting suspicion that the tough old Welsh waterman might be adept at putting men into the water, as well as pulling them out.