  Using resolved optical stellar photometry from the Panchromatic Hubble
Andromeda Treasury Triangulum Extended Region (PHATTER) survey, we measured the
star formation history (SFH) near the position of 85 supernova remnants (SNRs)
in M33. We constrained the progenitor masses for 60 of these SNRs, finding the
remaining 25 remnants had no local SF in the last 56 Myr consistent with
core-collapse SNe (CCSNe), making them potential Type Ia candidates. We then
infer a progenitor mass distribution from the age distribution, assuming single
star evolution. We find that the progenitor mass distribution is consistent
with being drawn from a power-law with an index of $-2.9^{+1.2}_{-1.0}$.
Additionally, we infer a minimum progenitor mass of $7.1^{+0.1}_{-0.2}\
M_{\odot}$ from this sample, consistent with several previous studies,
providing further evidence that stars with ages older than the lifetimes of
single 8 $M_{\odot}$ stars are producing supernovae.
