I want to know the answer to the following question:
Who was the Holy Roman Church leader that authorized the change ?
All the background I'm provided with is that "On 28 February 1476, Pope Sixtus IV, authorized those dioceses that wished to introduce the feast to do so, and introduced it to his own diocese of Rome in 1477, with a specially composed Mass and Office of the feast.". Is that enough to answer the question?
Answer: yes