Pentecost, also known as Whit Sunday, is one of the most significant feast days in the Christian calendar. It commemorates the descent of the Holy Spirit upon the Apostles and other followers of Jesus. This event is often referred to as the birth of the Christian Church because it marks the beginning of the Apostles' public ministry to spread the Gospel.

Orthodox Pentecost is one of the Great Feasts of the Eastern Orthodox Church. It commemorates the descent of the Holy Spirit upon the Apostles, marking the fulfillment of Christ's promise to send the Spirit to guide and empower the Church. Orthodox Pentecost is rich in theological significance, liturgical traditions, and cultural customs.

Pentecost Monday, also known as Whit Monday, is the day following Pentecost Sunday, celebrated by Christians to continue the commemoration of the descent of the Holy Spirit upon the Apostles. It is recognized in many parts of the world.

Orthodox Pentecost Monday is part of the Afterfeast of Pentecost, continuing the celebration of the descent of the Holy Spirit upon the Apostles. It is a day of significant liturgical and cultural importance in Eastern Orthodoxy, marked by prayers, traditions and community gatherings that honor the work of the Holy Spirit and the revelation of the Holy Trinity.

Corpus Christi, also known as the Solemnity of the Most Holy Body and Blood of Christ, is a significant feast in the Catholic Church that celebrates the Real Presence of Jesus Christ in the Eucharist. The name Corpus Christi is Latin for "Body of Christ".

St. John's Day holds cultural, religious, and historical significance, particularly in Quebec, Canada, where it is observed as a major holiday and an expression of Francophone pride and heritage.

The Feast of St. Peter and St. Paul honors the martyrdom of the Apostles Peter and Paul, two of the most significant figures in early Christianity. It is a solemn feast in both the Catholic and Orthodox Churches and is considered a Holy Day of Obligation in many Catholic regions.

Orangemen's Day, also known as The Twelfth, is a holiday celebrated by members of the Orange Order, a Protestant fraternal organization. The day commemorates the Battle of the Boyne, a significant historical event in Ireland.