Holy Week is the week from Palm Sunday to Holy Saturday, the most solemn of the Christian year, in which the church commemorates day by day the final events of Christ's life, from the entry into Jerusalem through the Last Supper, betrayal, trial, crucifixion and burial, to the vigil of the resurrection. Its distinctive feature is that it follows the events in something like real time, assigning each to its day and hour.
This "historical" or stational liturgy has a traceable origin. In fourth-century Jerusalem, as the pilgrim Egeria records in detail, the church began to keep each event at the very place and on the very day and hour it was believed to have happened, processing to the Mount of Olives, to Golgotha, to the tomb; pilgrims carried the practice home, and the whole Christian world gradually adopted a week that re-enacts rather than merely recalls. The last three days, the Triduum of Maundy Thursday evening to Easter, form a single continuous liturgy in the Western reckoning. Across traditions the week is marked by stripped altars, silenced bells, extended Gospel readings and, in many countries, large public processions, making it the most visible week of the Christian calendar.