The center of the medieval city was probably just a fairground south of the town hall and the only church in the village. The market place, originally smaller than the present and enlarged following a fire in the early 15th century, was eventually surrounded by permanent buildings and evolved into the present public square Stortorget ("The Large Square"), still located south of the so-called Stock Exchange and the Cathedral. While Stockholm is likely to have expanded quickly, it remains much debated if the expansion was planned in accordance to the model of southern prototypes (e.g. such as Lübeck) and, as historical sources traditionally have rendered it, governed directly by Birger Jarl (1210–1266) and Magnus Ladulås (1240–1290), or, as some historian have argued, a somewhat desultory if not entirely unmethodical process. Nevertheless, the medieval thoroughfares led from the large square in all four cardinal directions: Köpmangatan ("Merchant's Street") led east down to a second square by the water, "Fisketorget" ("Fishery Square"). Svartmangatan ("Black Man's Street", named after the Blackfriars monastery) and Skomakargatan ("Shoemaker's Street") led south to the financial centre of the city. Located where is today Järntorget ("The Iron Square"), this marketplace was at the time not much more than two landing stages separated by an open space on the southern corner of the island. On either side of this marketplace, considerably larger than the present square, was on its eastern side "Koggabron" (named after, cogs, a type of medieval merchant vessel) and today superseded by Skeppsbron, and on its western side was "Kornhamn" ("Corn Harbour") receiving the ships from Lake Mälaren, located near today's Kornhamnstorg. Trångsund ("Narrow Strait"), at the time much narrower than today, was leading north past the cathedral.