Christians came to the conclusion that Joachim and Ann were great people because they were the parents of Mary and the grandparents of Jesus, the Savior of the world, the Lord of lords, and God Himself. By their fruits you will know them (see Mt 7:20).
Christians, especially in the East, came to believe the tradition that Joachim and Ann presented Mary in the Temple when she was three years old. This was to prepare her to be the mother of God. By the Presentation of Mary, Joachim and Ann were making a statement about the importance of Mary in God's plan of salvation and the importance of discipleship for all Christians, including Mary. This tradition became so important that it was celebrated each year by the universal church on November 21. (This is the patronal feast day of Our Lady of Presentation Ministries, which publishes One Bread, One Body.)
Over a hundred years ago, the Church made official what had been preached and believed throughout Christian history. The Church proclaimed that Mary was immaculately conceived. The Immaculate Conception is a statement about Mary and especially about her Son, Jesus. Moreover, it says that Joachim and Ann were even more blessed than we have ever realized. Sts. Joachim and Ann, pray for us!