1976 advert for Castrol GTX.
Castrol is a brand of industrial and automotive lubricants which is applied to a large range of oils, greases and similar products for most lubrication applications. The Castrol brand is part of the BP Group of companies, but has retained its separate identity.
In February 1899, Charles Cheers Wakefield took what was perhaps the greatest risk of his working life: he resigned from the Vacuum Oil Company over a disagreement with the management regarding Vacuum Oil’s foray into the railroad lubricants sector, and set himself up as competition. The firm he left behind would go on to become Mobil Oil.
Wakefield rented three small rooms on the third floor of 27 Cannon Street in the heart of London, and it was there, on Thursday 9 March 1899, that the firm of C.C.Wakefield & Co opened its doors for the first time.
In 1909, the company began production of a new automotive lubricant named “Castrol” (a contraction of castor oil, from which it was made). The company developed specific oil applications for various applications of the new internal combustion engine, including cars, motorcycles, and aircraft. The original 3 grades of oil being CW for cars, C for motorcycles and R for aircraft and racing engines, the castor oil being responsible for the noticeable exhaust odor of early aircraft rotary engines.
In 1966, Castrol was acquired by British oil company Burmah, which was renamed Burmah-Castrol. In 2000, Burmah-Castrol was acquired by the then BP Amoco plc (now renamed BP plc). Castrol branded lubricants continue to be sold around the world and are, in many countries, market leaders.
Info gleaned from Wikipedia