We have obtained photometry and spectra of SN 1991T which extend more
than 1000 days past maximum light, by far the longest a SN Ia has been
followed. Although SN 1991T exhibited nearly photometric behavior in
the first 400 days following maximum, by 600 days its decline had slow
ed, and by 950 days the supernova brightness was consistent with a con
stant apparent magnitude of m(B) = 21.30. Spectra near maximum showed
minor variations on the SN Ia theme which grew less conspicuous during
the exponential decline. At 270 days the nebular spectrum was compose
d of Fe and Co lines common to SN Ia. However, by 750 days past maximu
m light, these lines had shifted in vavelength, and were superposed on
a strong blue continuum. The luminosity of SN 1991T at 950 days is mo
re than 9.0 x 10(38)(D/13 Mpc)(2) ergs s(-1) with a rate of decline of
less than 0.04 mag per 100 days. We show that this emission is likely
to be light that was emitted by SN 1991T near maximum light which has
reflected from foreground dust, much like the light echos observed ar
ound SN 1987A.