This is the outside of the Beauchamp Tower. It was constructed under the guidance of King Edward I during 1275-1281. It's noteworthy because of the many carvings done by prisoners while being held captive within the tower's walls.
The more complicated carvings and both beautiful in their intricacy and frightening when one considers how long the prisoner must have been in there to have completed it.
This especially intricate carving was done as a memorial to the five Dudley brothers and was likely carved by the eldest, John. The brothers and their father were all imprisoned at the Tower of London for assisting Lady Jane Grey in taking the throne that was declared rightful to Mary I.
This simple carving of the name "Jane" was likely made by Lord Guilford Dudley, who was the husband of Lady Jane Grey. His father and four brothers were released, but he was executed for high treason on the same day as his wife.