Another reason for me to not like the current Pope

[Alex]

It was his pope name.

His birth name was Felice Peretti.

Sadly, there does not seem to have been a Pope Sixtus the Sixth.

Sixtus I - 117-126 AD
Sixtus II - 257-258 AD
Sixtus III - 432-440 AD
Sixtus IV - 1471-1484 AD
Sixtus V - 1585-1590 AD

(Yes, I know it is redundant to include AD in Papal terms but I was just making it clear they were years.)