Pope Paul VI
Paul VI revolutionized papal elections by ordering that only cardinals below the age of eighty might participate in future conclaves. In Ecclesiae Sanctae, his motu proprio of 6 August 1966, he further invited all bishops to offer their retirement to the pontiff no later than the completion of their 75th year of age. This requirement was extended to all Cardinals of the Catholic Church on 21 November 1970. With these two stipulations, the Pope filled several positions with younger bishops and cardinals, and further internationalized the Roman Curia in light of several resignations due to age.

Q: What did Paul VI over hall with age and retirement restrictions?
papal elections