BMW launched the first-generation 5 Series in 1972. Known internally as the E12, it replaced the BMW New Class sedans and established the 5 Series name that BMW continues to use for its executive-car range.
The E12 was introduced in 1972 with the four-cylinder 520 and fuel-injected 520i. A six-cylinder model followed in 1973, broadening the range and reinforcing the smooth, rear-wheel-drive character associated with the series. BMW initially built the cars in Munich, then gradually moved production to the new Dingolfing plant after it opened in 1973.
The year can cause confusion because some markets treated the car as a 1973 or 1975 model-year vehicle, especially in North America. The question asks when BMW launched the first generation, rather than when a particular market received it or when the model-year designation began. The E12 was replaced in most markets by the E28 in 1981, although South African production continued later.