The eucharistic fast was changed from midnight to three hours before communion by Pope Pius XII in 1953, with his decree. *Christus Dominus. *This originally was for Sundays and holy days only.
papalencyclicals.net/Pius12/P12CHDOM.HTM
Its guidelines were extended by Pius XII in 1957 to include weekday Masses.
ewtn.com/library/PAPALDOC/P12FAST.HTM
The one-hour fast was established in 1966 by Pope Paul VI, at which time he also gace bishops’ conferences authority to determine rules of Friday abstinence.
adoremus.org/PaulVI-Penance.html
Permission for Saturday evening anticipated Masses (a somewhat different concept from a traditional Vigil Mass) was given in different times and locations, but it was universally recognized in 1967 by Paul VI in number 28 of
Eucharisticum Mysterium.
adoremus.org/eucharisticummysterium.html