Guardians of St. George's Chapel, Windsor Castle.
St. George's Chapel at Windsor Castle has a long and interesting history. It has been the location of many Royal weddings as well as even more Royal burials. Among those buried there are included Kings George III, IV, V and VI, as well as another King George V of Hannover. Recent interments in the chapel have included the Queen's sister, Princess Margaret, and her mother, Elizabeth the Queen Mother. Historical figures buried there include Henry VIII and one of his wives, Jane Seymour. See Wikipedia: http://en.wikipedia.org/wiki/St_George's_Chapel,_Windsor_Castle#Royal_Vault
This photo is actually only a quarter or so of the original JPEG frame- just another example of finding the photo I should have taken after it was too late.
I have no idea what filters or other applications were used on this besides Lightroom and Photoshop. It's been quite a while since my original processing, and I added a little more tweaking in the current version of Lightroom for this export.