It has happened about 50 years ago at the old Munich airport in Germany. The date was August 15, a Catholic holiday called Maria Ascension Day.
In those days, there were often quiet moments over the radio. In one of these silent moments, a booming voice came over the R/T:
Unidentified Pilot:
“This is Maria, still climbing.”
Radar:
“No restrictions on your climb.”
Hans Koeners
via e-mail