The firm was created through the merger of Poland's two communist oil monopolies. PKN Orlen has its roots in the creation of C.P.N., Communist Poland's petroleum retail monopoly in 1944. In the 1950s, the second block of PKN Orlen was formed, Petrochemia Płock, a state firm in charge of the refineries in Płock and grew to become the largest complex of its kind in Poland. After the merger of CPN and Petrochemia Plock, the company was renamed into Polski Koncern Naftowy (PKN), with Orlen added several months later as the consortium's brand name. The new name is derived from Orl- for "orzeł" (Polish: eagle) and its adjective "orli", and -en for "energia" (Polish: energy).