In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Dolwyddelan like this:
DOLWYDDELAN, a village and a parish in the district of Llanrwst and county of Carnarvon. The village stands on the river Lledr, under Moel-Siabod, amid most sequestered mountainous environs, 7 miles SW of Llanrwst r. station; and has a post office under Conway. The parish comprises 14, 384 acres. ...
Real property, £1, 974; of which £98 are in quarries. Pop., 811. Houses, 164. The property is all in one estate. Dolwyddelan Castle, crowning a rocky steep, and including a massive square tower, dates from the 5th or 6th century; belonged to the Welsh princes; was the birth-place of Llewelyn the Great; and passed to the Berkenets, Meredith ap Evan, and the Gwynnes. The living is a vicarage in the diocese of Bangor. Value, £107. Patron, Lord Willough-by de Eresby. The church is good; and there are chapels for Independents and Calvinistic Methodists.
GB Historical GIS / University of Portsmouth, History of Dolwyddelan, in Conwy and Caernarvonshire | Map and description, A Vision of Britain through Time.
Date accessed: 24th March 2017
Click here for more detailed advice on finding places within A Vision of Britain through Time , and maybe some references to other places called " Dolwyddelan ".