John Rocque's Old Maps: London, 1737-1747. John Rocque is now mainly remembered for his Map of London, which he began in 1737. It was published in 24 printed sheets in 1747. It was by far the most detailed map of London published up to that time and remains an important historical resource. The map of London and his other maps brought him an appointment as cartographer to Frederick, Prince of Wales in 1751.