Although sister cities were originally forged for military or political ties, this has expanded considerably and today twin cities focus on cultural exchanges, education, economics and trade relations. Today, more than 2,000 cities, states and counties are partners in more than 140 countries around the world. The first known twinning in Europe was between Paderborn, Germany, and Le Mans, France, in 836.   From 1905, Keighley, in West Yorkshire, England, had a twinning with the French communes of Suresnes and Puteaux.   The first modern twinning recorded between Keighley and Poix-du-Nord in the North, France, in 1920, after the end of the First World War.     It was originally the adoption of the French city; Formal partnership charters were not exchanged until 1986.  In general, friendship cities are less formal than twin cities. A friendship contract is often used as a first step in the urban relationship. If it strengthens and both parties later decide to want a long-term relationship, they will become twin cities. The history of a twin city goes back centuries.
Paderborn and Le Mans, France, were the first in Europe to establish the form of partnership of a ”buried fraternity” between the dioceses of the two Andean Catholic bishops. Subsequently, an official twinning contract was signed in 1967. A twin city relationship must expand, strengthen and bring great benefits to both parties. This voluntary engagement agreement helps to promote business, trade, education, cultural exchanges and projects between twin cities. On the occasion of the 50th anniversary of their urban relationship in 1981, the mayor of Toledo, Spain, gave a speech on the friendship between the two cities. The agreement was signed as part of the U.S.-India State and Urban Initiative, led by the Washington-based Center for Strategic and International Studies (CSIS) to strengthen clean technology cooperation between the two regions. The Minister informed the Governor that he had lived in New Jersey during his stay in the United States and indicated that this was one of the areas where there was a large Indian presence. Areas identified for link growth would give Telangana a boost, he noted. Becoming a partner city is a modern process in which trust is established and a strong relationship with the desired partner city.
These partnerships can be developed in different ways, such as: for those new to the term ”sister cities” (or ”twin cities”) almost a rather bizarre, picturesque and perhaps even fantastic feeling. If you didn`t know better, you`d forgive thinking of enchanted fantasy countries or something of a science fiction novel. In the United Kingdom, the term ”twin cities” is the most widely used; the term ”sister cities” is generally used for agreements with cities in North and South America.   On the European continent, the most commonly used terms are `twin cities`, `twin cities`, `twin cities` and `friendship cities`. The European Commission uses the term `twin cities` and refers to the process as `twinning cities`.   Spain uses the term ”ciudades hermanadas,” which means ”sister cities.” Germany, Poland and the Czech Republic use the partner city (De) / miasto partnerskie (Pl) / partnerské mesto (Cz), which means ”partner city” or ”partner city”. France uses twin city (twinning, twinning city or city) and Italy a gemellaggio (partnership) and comune gemellato (common partner).  In the Netherlands, the terms ”Partnerstad” or ”Stedenband” (”urban borrowing” when it comes to mutual assistance).