The following chart plots the FTSE All Share Index from 1700 (log scale) and the years of new popes (indicated by the grey vertical bars).
Pontificates of long duration have tended to coincide with strong equity markets. During the pontificate of John Paul II (1978-2005) the UK market rose 2800%. Whereas periods of short duration pontificates have coincided with weak or flat equity markets.
Summary: investors like long popes.