The Tweet, roughly translated from Latin, means "We have Pope Francis."
"It seems unimaginable that one could continue to use a communication tool so popular and powerful during the sede vacante period," Vatican Radio said at the time, in reference to the period where no pope presided over the world's 1.2 billion Catholics.
The Twitter handle is not name-specific. The word "pontifex" comes from the Latin word meaning "bridge builder."
Tweets sent during Benedict's papacy have seemingly been deleted. The account's only followers are the other @Pontifex accounts that send out Tweets in different languages.
When Benedict was Pope, about 1.5 million of @Pontifex's Twitter followers subscribed to the English language feed. Nearly 700,000 followed @Pontifex's Spanish tweets and about 335,000 followed in Italian. About 22,500 people followed @Pontifex in Latin.
Pope Benedict was 85 when he first tweeted in December.
"Dear friends, I am pleased to get in touch with you through Twitter. Thank you for your generous response. I bless all of you from my heart," he tweeted from an iPad and then used TweetDeck to send his next six modern-age missives.
It remains to be seen how active the new pope will be on Twitter. He was not among the nine or so cardinals known to have active Twitter accounts.