Today he toasted his brother Georg on his 90th birthday, celebrating Mass together and attending a concert in the Vatican gardens.
Monsignor Georg Ratzinger was ordained a priest the same day as the future pope in 1951 and they share a love of music. Ratzinger was a frequent visitor when Benedict, 86, was pope and has continued visiting in Benedict's retirement.
The brothers spent Christmas together at Benedict's retirement home in a converted monastery in the Vatican gardens, and Ratzinger stayed on a few weeks so they could celebrate his birthday together.