Pope Pius VII (1742 – 1823) that couldn't be who you're thinking of.
Correction: Pope Pius XII is the last true pope that we have had for 50+ years. (Thank you mrs. Don-o!)
Forgive me all, the twelfth is what was intended!
(Pius XII of fond memory died around anno Domini 1958.)
Since then a usurpation of the papacy and the apostasy of many in Rome and around the world has taken place with the perversion of the worship, especially launched with so-called Vatican II and promulgated by anti-popes who assumed the titles falsely in my lifetime.
There are priests today who continue the Mass as it was in its legitimate form prior to false popes and council. Pray the rosary. Live the faith as taught in traditional catechism. Worship regularly at a traditional parish if possible. Avoid the Novus Ordo (New Order) groups. They practice heresy.
As Paul the apostle said, do not abandon the traditions taught you. Recent “popes” have this common abandoning of tradtition thread throughout their lives.