The W110 was Mercedes-Benz's entry level line of midsize automobiles in the mid-1960s. One of Mercedes' range of "Fintail" models, the W110 initially was available with either a 1.9 L M121 gasoline or 2.0 L OM621 diesel inline-four. It was introduced with the 190c and 190Dc sedans in April 1961, replacing the W120 180c/180Dc and W121 190b/190Db.

The Mercedes-Benz M121 engine was a 1.9 liter single overhead camshaft inline four-cylinder engine introduced by Mercedes in 1955 and used in various model lines during the 1950s and 1960s. Originally rated at 56 kW at 5500 rpm, it replaced the 1.8 liter M136 introduced in 1935, offering improved performance over the M136's side camshaft design.