Question: When did the holy spirit descended upon the apostles?
Disambiguated questions and answers: question: When did the holy spirit actually descend upon the apostles?
When do we celebrate the holy spirit descending upon the apostles?
answer: while they were in Jerusalem celebrating the Feast of Weeks
the feast of weeks
Whitsun
Pentecost
White Sunday
fifty days after Easter Sunday
Whitsunday
Natural Questions answer: day of Pentecost (from the Wikipedia article "Pentecost")