The first Cadillac car was completed on October 7, 1902 and the following January was shown at the New York Auto Show, where it impressed the crowds enough to gather over two thousand firm orders. The Cadillac's biggest selling point was its refinement; it was simply a better made vehicle than its competition.
Cadillacs were sent to England, where in Feb.-Mar. 1908, three late 1907 Model K's successfully completed the Royal Automobile Club's Standardization Test. As a result of these test results, the Cadillac Automobile Company was awarded the Dewar Trophy for 1908 (actual award date was Feb., 1909). The Dewar Trophy was an annual award for the most important advancement of the year in the automobile industry.
Cadillac was purchased by the General Motors conglomerate in 1909 and became General Motors' prestige division, devoted to the production of large luxury vehicles.
In 1911 Cadillac was the first gasoline internal combustion engine auto to incorporate electric self-starting (as opposed to earlier crank start), utilizing the electric starter developed by Charles Kettering. Other innovations included the first V-8 engine in mass production, in 1915; shatter-resistant safety glass in 1926; and the first fully synchronized transmission (with gears "locked" in relation to one another to prevent clashing upon execution of a shift) in 1928. About this time, Cadillac acquired a smaller "companion" car called the LaSalle, which lasted until 1940.
Pre-World War II Cadillacs were well-built, powerful, mass-produced luxury cars, aimed at an upper class market, below that of such ultra-exclusive marques such as Pierce-Arrow and Duesenberg. In the 1930s, Cadillac added cars with 12 and 16 cylinder engines to their range, many of which were fitted with custom coach-built bodies. These engines were remarkable at the time for their ability to deliver a combination of high power, silky smoothness and quietness.
Postwar Cadillacs, incorporating the ideas of General Motors styling chief Harley Earl, innovated many of the styling features that came to be synonymous with the classic (late 1940s-late 1950s) American automobile, including tailfins and wraparound windshields. Cadillac's first tailfins, inspired by the twin rudders of the Lockheed P-38 Lightning, appeared in 1948. The 1959 Cadillac was the epitome of the tailfin craze, with the largest tailfins of any production automobile. With their chromed, bulleted bumpers (the bullets were nicknamed "Mansfields" or "Dagmars", after their resemblance to the breasts of certain Hollywood starlets), chromium eggcrate grilles, and general stylistic ostentation. The late 1950s Cadillacs were arguably too extreme even for most Cadillac buyers.
At this point, Bill Mitchell succeeded Harley Earl as styling chief, and his preference for more austere design combined with changing buyer tastes caused the excess to be rapidly toned down in the early 1960s. Nevertheless, Cadillacs retained their tailfins through 1964, and suggestions of them remained in the peaked rear fenders of many models into the 1990s.