Polarimetry of powerful radio galaxies from z=0 to z=4

The advent of sensitive polarimeters on large telescopes has led to a revolution in our understanding of active galaxies over the last 20 years. In the case of powerful radio galaxies the deep polarimetric measurements made possible by the new technology have: (a) provided the most direct evidence to support the unified schemes for powerful radio galaxies; (b) enhanced our understanding of the colours and morphologies of radio source host galaxies at all redshifts; and © provided key information about the kinematics and geometries of the scattering regions on a sub-kpc scale.