The archangels are leaders of angels in the army of God. These three archangels are mentioned in scripture. Their feast day is on September 29.
St. Ignatius of Loyola is the founder of the Society of Jesus, also known as the Jesuits. He was pursuing a career in the military when a cannonball shattered his leg. While recovering, he discovered that reflecting on the things of this world, such as fame and romance, only brought him temporary pleasure. Reading about the lives of the saints and thinking about serving Jesus Christ brought him lasting happiness.
June 28 is the feast day of St. Irenaeus. He was an early Christian theologian who argued against the gnostics in his extensive writings.
April 21 is the feast day of St. Anselm of Canterbury: philosopher, theologian, and Doctor of the Church.
April 4 is the feast day of St. Isidore of Seville: a bishop and a scholar who wrote a huge encyclopedia. He is the patron saint of the internet, computer users, programmers, and students.
March 17 is the Feast of St. Patrick. St. Patrick is the patron saint of Ireland, engineers, and paralegals. He is especially known for using the image of the shamrock to explain the Holy Trinity.