The Fifth Doctor had resolved to take Peri Brown and Erimem to London in 1485 to investigate the historical mystery surrounding King Richard III of England and the princes he reportedly kept in the Tower of London. The Doctor's TARDIS accidentally materialised in 1483, when Peri and Erimem exited under instructions from the Doctor to meet him at the Kingmaker. The TARDIS then dematerialised and re-materialised at its target coordinates, two years later.