Christian holidays are celebrated throughout the year by most denominations of Christianity. Feast days celebrate joyous events like the birth of Christ, while fast days provide a special opportunity for self-reflection and repentance. Some Christian holidays have come to have a considerable impact on western culture and traditions.
The oldest and most important Christian holiday is Easter, a spring holiday that celebrates Jesus Christ's resurrection from the dead. This event was originally celebrated every Sunday (the "Lord's Day").
Saints' days are also important to most Christian denominations. Some of these, such as St. Patrick's Day and St. Valentine's Day, have come to play a prominent role in popular western culture. Other holidays with Christian origins that are now mostly secular celebrations include Mardi Gras and Thanksgiving.