Easter has been celebrated on a spring Sunday since 325 AD. That is when the Nicean Council decided that Easter should be celebrated on the first Sunday after the first full moon after the Spring Equinox, unless the first full moon also rose on a Sunday, in which case Easter would be celebrated the Sunday after that. Easter Sunday still adheres to these rules.
Easter follows two other major religious time periods in Italy... First there's Carnevale, during which feasting is enjoyed before the second period... Lent (Quaresima in Italian), during which Christians mimic the forty days Christ spent fasting in the desert before suffering His fate on the cross.
As a child, my family observed meatless Fridays but rarely gave up meat during Lent, but in the old days, Catholics were expected to give up far more during Lent: meat, eggs, milk and even fats. This is the reason why many consider the Tuesday before the commencement of Lent as "Fat Tuesday" or Martedì Grasso. People would have one last blast, eating pretty much everything they could that was on the banned list, before the more lean days of lent.
During Lent there is the Italian Version of Father's Day, la Festa di San Giuseppe on March 19th. Then one week before Christ's resurrection on Easter Sunday, there is Palm Sunday, which Italians celebrate with the blessing of olive branches and palm leaves in church, celebrating Jesus' arrival in Jerusalem. Priests in Italy knock three times on the church door to symbolize Christ entering. During Lent, many also ask their local priest to bless their homes.
Right before Easter Sunday is Holy Thursday, celebrated as la Missa in Cena Domini (the Mass of the Last Supper), during which the priest washes the feet of twelve members of the congregation to represent His Apostles.
Next is Holy Friday when Jesus died on the cross, a big deal in the Catholic faith, but an even bigger deal in Italy. Every church has an afternoon mass (bells ring at 3pm) where there is typically a reenactment of the Passion of Christ is celebrated, complete with costumed people and Jesus carrying a large cross. On TV, the Passion is watched from people's homes.
Right before Easter is Holy Saturday when a solemn mass is held without music or singing and late in the evening there is la Veglia di Pasqua (the Easter Vigil), one of the holiest times for Catholics... waiting for Jesus to rise again.
In the Sicilian town of Pietraperzia, thousands celebrate on Good Friday with the celebration called U Signuri di li fasci (Lord of the bands), when families tie large white ribbons onto a central large crucifix in the piazza, looking like a huge Maypole. This ritual has gone on since the year 12th century for each family in the town to make a solemn pledge of loyalty to Christ.