We have measured the zero-field muon spin relaxation (ZF mu(+)SR) spec
tra of the quasi-one-dimensional fulleride conductor CsC60. Static mag
netic order of a random nature develops gradually below about 30 K. Th
e local field distribution at the muon site has a Gaussian shape with
a width of 48.3(7) G at 2.8 K. Muon spin rotation (TF mu(+)SR) measure
ments at an applied transverse field of 6 kG also show the onset of ma
gnetic order in the same temperature range.