If you've read the news today, you probably know that the remains of Richard III have been found in Leicester, England, underneath what was recently a parking lot. When Richard III was killed in battle, the site was occupied by the chapel at Greyfriars, a church that was later razed during the Restoration. It appears he may have been buried with his wrists tied together, and the grave wasn't quite long enough for his frame, so his head was in a bad position. No wonder he was discontent.
Richard's remains were identified by forensic evidence including circumstances (including location, wounds, and the scoliosis of the spine), carbon dating and DNA testing, and the results were positively identified here. If you're interested in hearing more about the historical Richard III and his treatment at Shakespeare's hands, you can read a past post from Brush Up Your Shakespeare Month a few years back.