What Twitter account name did Pope Benedict XVI join under in 2012?

Pope Benedict XVI joined Twitter in 2012 under the account name @pontifex.

The Vatican announced the account in December 2012, giving the pope a digital channel for short public messages. His first tweet was posted on December 12, 2012, and thanked followers before offering a blessing. The account was presented as a papal presence rather than a personal account using Benedict’s birth name, Joseph Ratzinger.

The Latin word “pontifex” means “bridge-builder” and is associated with the pope’s title, Pontifex Maximus. The handle was therefore designed to outlast one pontificate. When Benedict resigned on February 28, 2013, the account was archived and displayed “Sede Vacante,” meaning the papal see was vacant.

After Francis was elected, the @pontifex account was handed to him, and it later continued under succeeding pontiffs. That continuity is why @pontifex is the canonical answer, rather than @benedictxvi or a generic Vatican-related name.