The first appearance of the many German Grand Lodges dates from the 1740s, notably "Of the Three Globes", founded in Berlin in 1744, which became the "Grand National Mother Lodge" in 1772. Frederick the Great became a Freemason while he was still Crown Prince and personally sanctioned the Berlin Lodge. Although a few authors cite the existence of German operative grand lodges as far back as that formed at Cologne Cathedral in 1250, continuity of tradition has been hard to prove, and most sources believe the Eighteenth-century German speculative lodges show descent from the English model.