The title “sister city” is used to describe a cooperative agreement between two communities in different parts of the world, with the goal of learning about each other and forming and promoting both commercial agreements and cultural ties. Usually, communities that form a sister city partnership are similar in size and demographics. These partnerships are formed for a variety reasons, such as business interests, similar industries, or shared history. The long-term partnership agreements are meant to support both sides of sisterhood and promote friendship and trust between peoples of different cultures.
The term “sister city” is used mainly in the U.S., although the concept has been around for centuries. In Europe, these partnerships are called “twin towns” or “town twinning.” The first incident of this type of partnership occurred in 836 AD when the town of Paderborn in Germany partnered with Le Mans in France. In the United States, the first city to form such an agreement was Toledo, Ohio, becoming the sister city to Toledo, Spain in 1931. Eventually, through President Eisenhower’s interest in a citizen diplomacy venture following World War II, the nonprofit organization Sister Cities International was formed in 1956 as part of the National League of Cities, becoming its own separate entity in 1967, and aiding the formation of sister city agreements ever since.