As currently constituted, AstraZeneca is the result of mergers extending back to the 19th century.
Four companies, all established between 1870 and 1919, underwent a merger in 1926 to become ICI (Imperial Chemical Industries).
In 1993 a demerger occurred in which ICI split off its chemical and pharmaceutical business, producing Zeneca, which–six years later–merged with Astra AB of Sweden to form the current company.
Astra AB had been founded in Sweden in 1913 as an international group focused on gastrointestinal, respiratory, cardiovascular and pain control products.
Zeneca, headquartered in London, was a bioscience entity engaged in R&D, marketing and producing pharmaceuticals focused on central nervous system, heart and anesthesia–as well as special chemicals and healthcare provision.