Such customs as that of fixing plaques or statues of our Lady on oak-trees, or of giving these shrines titles of ‘Our Lady of the Oak', were both widespread and ancient. There was a famous Virgin of the Oak in Norwich and, according to tradition, our Lady of Penrhys, burned at Chelsea with our Lady of Willesden and our Lady of Walsingham, was found by shepherds hanging on the trunk of an oak on the summit of a mountain at the head of the Rhondda Valley. There is reason, too, to suppose that our Lady of Willesden may have been yet another instance of what was originally an oak-tree sanctuary.
By far the most important shrine, however, of this particular cultus of our Lady still survives in Central Italy, in the Shrine of St Maria della Quercia (Oak-tree), just outside the Porta Santa Lucia at Viterbo, on the road to Bagnaia.