  We present the results of a radio polarimetric study of the high-redshift
radio galaxy PKS B0529-549 (z=2.575), based on high-resolution 12 mm and 3 cm
images obtained with the Australia Telescope Compact Array (ATCA). The source
is found to have a rest-frame Faraday rotation measure of -9600 rad m^{-2}, the
largest seen thus far in the environment of a z > 2 radio galaxy. In addition,
the rest-frame Faraday dispersion in the screen responsible for the rotation is
calculated to be 5800 rad m^{-2}, implying rotation measures as large as -15400
rad m^{-2}. Using supporting near-IR imaging from the Very Large Telescope
(VLT), we suggest that the rotation measure originates in the Ly-alpha halo
surrounding the host galaxy, and estimate the magnetic field strength to be ~10
microGauss. We also present a new optical spectrum of PKS B0529-549 obtained
with the New Technology Telescope (NTT), and propose that the emission-line
ratios are best described by a photoionization model. Furthermore, the host
galaxy is found to exhibit both hot dust emission at 8.0 microns and
significant internal visual extinction (~1.6 mag), as inferred from Spitzer
Space Telescope near/mid-IR imaging.
