The IPhT was created in 1963 as the "Service de Physique Théorique" (SPhT), in succession of the "Service de Physique Mathématique" (SPM) of CEA. It became an Institute (and took the name IPhT) in 2008. It was initially devoted to nuclear physics and superconductivity. Particle physics quickly became an important theme. After its move in 1968 from the main CEA-Saclay site to the present site of Orme des Merisiers, quantum field theory became a major research topic, together with statistical physics. Subsequently, new topics such as conformal theories and matrix models, cosmology and string theory, condensed matter physics and out-of-equilibrium statistical physics, quantum information, found their place there. IPhT is usually considered one of the top theoretical physics research institute in Europe.