Eucharistic Prayer mentioning a Pope

In Paul Turner's Blog by Paul Turner

Q:  This was asked of my by one of our priests:
When is the first instance in the Eucharistic Prayer of the mentioning a Pope by name? Do we have any context or commentary as to why the name was added to the Anaphora at that time?
He suspects that it came at a time in history after the papacy faced difficult days – not unlike today.
Any thoughts?
A:  Regarding the name of the pope in the Roman Canon, it’s in place by the 7th century Gelasian Sacramentary. It’d be really hard to figure out what prompted its inclusion. On p. 72 of my book At the Supper of the Lamb, I indicate that because the Roman Canon is Roman, it probably started with a prayer for the local bishop, who just happened to be the pope.