The S-Class became Mercedes-Benz' flagship line in 1972 and still is even up to the present. The 'S' signifies "Sonderklasse" or special class and is mostly a 4-door sedan line with a brief appearance of coupes from 1981 to 1997. The S-Class is currently in its 5th generation.
The W116 was the first ever line to be officially called S-Class. It was sold alongside the
600 as the most luxurious Mercedez-Benz in the 70's. It replaced the
W109 as the top sedan line. Released in 1972, the first 3 models were the 280S, 280SE and 350SE. In 1973, the 450SE was added along with long wheel base models: the 350SEL and 450SEL. The 280SEL wasn't added until 1974. In 1975, a new top model was introduced, the 450SEL 6.9 and in 1978, a diesel version was added, the 300SD. The 2nd generation of the S-Class line, the
W126, was released in 1979 but all the W116 models lasted up to 1980.