Hanseatic League (hăn´sēăt´Ĭk, hăn´zē–), mercantile league of medieval German towns. It was amorphous in character; its origin cannot be dated exactly. Originally a Hansa was a company of merchants trading with foreign lands. After the German push eastward and the settlement of German towns in the Slavic lands of the Baltic, the merchant guilds and town associations led (13th cent.) to leagues. Most notable was the company of German merchants with headquarters at Visby; pushing east, they founded a branch at Novgorod. In London, where German merchants had traded since the 11th cent., the privileges granted to Cologne merchants were extended to other Germans, and a Hansa of German merchants was formed (see Steelyard, Merchants of the). A major impetus to the league's development was the lack of a powerful German national government to provide security for trade. In order to obtain mutual security, exclusive trading rights, and, wherever possible, trade monopoly, the towns drew closer together. In 1241 Lübeck and Hamburg concluded a treaty of mutual protection. Other cities joined this association, and a strong league grew up led by Lübeck. Ports and inland towns from Holland to Poland entered the league, but the north German cities remained the principal members. The league vigorously extended its operations, founding principal foreign branches at Bruges and Bergen. The Hansa towns reached their summit in their victories over Waldemar IV of Denmark, gaining in the Treaty of Stralsund (1370) a virtual trade monopoly in Scandinavia. Their Baltic hegemony continued through numerous wars until their defeat by the Dutch in 1441. Despite its success, the league suffered from lack of organization. Although assemblies of the league met irregularly at Lübeck, many towns did not send representatives, and decisions were subject to review by the individual towns. The number of members fluctuated, probably from less than 100 to over 160. By the 16th cent. internal dissension, curtailment of freedom by the German princes, growth of centralized foreign states and consequent loss of Hanseatic privileges, advances of Dutch and English shipping, and various changes in trade all operated against the league. The last diet was held in 1669, but the league was never formally dissolved. Lübeck, Hamburg, and Bremen are still known as Hanseatic cities.
See P. Dollinger, The German Hansa (tr. 1970).