In the early church, there were no specific Holy Days (or holidays) to recognize the Resurrection. Christians gathered every single Sunday, or Resurrection Day to celebrate. They took communion together virtually every time they gathered.
Then, in 312 a.d. the Roman Emperor Constantine had a dream about Jesus before an important battle, and suddenly Christianity was the “official” religion of the Roman Empire. This began the form of faith that later evolved into the Roman Catholic Church, which, even if you’re Protestant, has shaped your faith far more than you think.
At the news of Constantine’s conversion, Christians living in Jerusalem reenacted Jesus’ entry into their city, complete with Palm branches and “hosannas”. This was the first recorded remembrance of the events that we call Palm Sunday.
By the late 8th or early 9th century, Palm Sunday had become a recognized Holy Day in the Roman church. Palm branches were “blessed,” a special Mass was observed, then those palm fronds were burned, the ashes to be used the following year on Ash Wednesday at the beginning of Lent. These observances continue in much the same form up to the present day in Catholicism.
After the Protestant reformation of the 16th century, the spiritual descendants of Martin Luther didn’t break that far from Rome in terms of the liturgy and the church calendar; but those in the lineage of John Calvin and other reformers rejected virtually all the Holy Days of the past thousand years.
When the Puritans (Calvinists) came to America, they refused to observe either Christmas or Easter. In fact, it was only after the Civil war in the late 1800’s that American churches, led by the Presbyterians, felt that what the nation needed in order to heal was a specific time each year to focus on the events of Jesus’ Resurrection.
From the early days of Roman celebration, Easter customs from other places around the world began to be incorporated, including pagan fertility rites associated with spring, including Easter eggs and bunny rabbits.
And that in a nutshell, is how we come to be doing what we do in our culture regarding Holy Week.