This picture illustrates the lines from Tennyson's "Vivien" idyll, later renamed "Merlin and Vivien":
Before an oak, so hollow, huge and old
It looked a tower of ivied masonwork,
At Merlin's feet the wily Vivien lay.
Before an oak, so hollow, huge and old
It looked a tower of ivied masonwork,
At Merlin's feet the wily Vivien lay.