
Snowdonia, also known as Eryri, is a mountainous region in North Wales and an 823-square-mile national park. It was once the site of ancient stones which the Celtic pagans worshipped into the late 9th century AD (in secret after the Christianization of Wales), and it is still home to Snowdon, the highest mountain in Wales. During the Middle Ages, Llywelyn the Great and Llywelyn ap Gruffudd both used the title "Lord of Snowdonia" in addition to their title of "Prince of Wales". In 1951, Snowdonia became a national park, and, by 2011, Snowdonia had 26,000 residents, with 58.6% being Welsh-speakers.