It started with an encounter in 1967 with Alexander King, the Director General for Scientific Affairs for the OECD in Paris at that time. Peccei and King decided to organize a meeting on 7-8 April 1968 of around thirty scholars at the Accademia dei Lincei in Rome, to discuss their ideas about the global aspects of problems facing mankind and of the necessity of acting at the global level. The meeting at the Accademia dei Lincei was not a success, partly due to the difficulty of the participants to focus on a distant future. After the meeting, there was an informal gathering of a few people in Peccei’s home, which included Erich Jantsch, Alexander King, and Hugo Thieman. The Club of Rome grew out of this meeting of minds and people who were focused on the same problem.
More information is available on the Aurelio Peccei Website...