The Great Oak at the Gates of the Dead is a 1,200-year old oak near Wrexham on the English/Welsh border. It marks the site of the battle of Crogen, 1165, when Owain Gwynedd defeated Henry II's force.
The BBC site has news that ice has caused the great oak to split down the middle, with more background and links .
More ancient trees in this previous post.
photo credit: thetreehunter via flickr.