Havelock the Dane, but historians see this account as a myth. In Norse mythology, Grim (Mask) and Grimnir (Masked One) are names adopted by the deity Oðin (Anglo-Saxon Woðen) when travelling incognito amongst mortals, as in the short poem known as "Grimnir's Sayings" (Grimnismal) in the Poetic Edda. The intended audience of the Havelock tale (recorded much later as the Lay of Havelock the Dane) may have taken the fisherman Grim to be Odin in disguise. The Oðinic name "Grimr/Grim" occurs in many English place names in the historical Danelaw and elsewhere in Britain. Examples are numerous earthworks named Grimsdyke. Other British place names with the element Grim are explained as referring to Woðen/Oðin (e.g. Grimsbury, Grimspound, Grime's Graves, Grimsditch, Grimsworne), and Grimsby is likely to have the same derivation. Grimsby is listed in the Domesday Book of 1086 as having a population of around 200, a priest, a mill, and a ferry. Medieval times Grimsby grew in the 12th century into a fishing and trading port, at one time ranking twelfth in importance to the Crown for tax revenue. The town gained its charter from King John in 1201; the first mayor was installed in 1202. Grimsby is noted in the in this stanza by Kali Kolsson: Grimsby had no town walls. It was too small and felt to be protected by the marshland around it. However, the town dug a defensive ditch. Grimsby in medieval times had two parish churches, St Mary's and St James. Only St James, now Grimsby Minster, remains. It is associated with a folk tale of an imp who played tricks in the church and was turned into stone by an angel. (A similar tale is told of Lincoln Cathedral – See Lincoln Imp). In the mid-14th century, the town benefited from the generosity of Edmund de Grimsby, a local man who became a senior Crown official and judge in Ireland. In the 15th century, The Haven began to silt up, preventing ships in the Humber from docking. As a result, Grimsby entered a long period of decline until the late 18th century. By 1801, the population of Grimsby numbered 1,524, around the size it had been in the Middle Ages. By 1810 Joseph Smedley was hiring a purpose built theatre for seven Guineas. Rise of fishing and maritime industry The Grimsby Haven Company was formed by Act of Parliament in May 1796 (the