Quam singulari
Quam singulari was a decree released by Pope Pius X in 1910, concerning the admittance of children to the Eucharist. There was a concern in the church about the practice of operating with different ages for admitting first Communion and first Confession. Some argued that, while reaching the age of reason was enough to receive first Confession, "a full knowledge of matters of faith" was needed to receive the first Communion. This, according to the "Quam singulari", was in error. In evidence of this, the decree referred to historical authorities such as the Lateran Council of 1215, the  teachings of St. Thomas Aquinas and St. Antoninus, the practices of the early church and Christ's own sayings on children. It was therefore stressed that this decree did not institute a new doctrine, but simply clarified ancient ones. The adverse opinion it discredited as Jansenist. The main concern of the Vatican was that the first, childlike innocence of the children should be lost, and that they should be allowed to fall into a state of sin before the first Communion was admitted. To avoid this, it was decreed that: