The European Solar Telescope (EST) is a pan-european project (with 29 partners, plus 7 collaborating institutions, from 14 countries) for the conceptual design study of a 4-meter class solar telescope promoted by the European Association for Solar Telescopes (EAST) to be located in the Canary Islands. The telescope, in the conceptual study, provides a Coudé focus with an F/50 telecentric beam. It is diffraction-limited in a FOV of 1 arcmin and it will be optimized in throughput for several instruments observing simultaneously in a spectral range from 0.39 μm to 2.3 μm. Its innovative concept integrates an optical transfer stage assembling multiconjugated adaptive optics with optical field de-rotation and with a perfect balance of the whole system in terms of polarization being time and wavelength invariant.