Besides being my birthday saint, Pius X is important to me for a reason related to the message of My Peace I Give You: the protective love he bore for children.
In 1910, he approved a decree, Quam singulari, condemning the practice of making children wait until age ten or older to receive First Communion. He ordered that children should be permitted to receive the sacrament at the age of reason—specifying that age as "when one can distinguish between the Bread of the Holy Eucharist and ordinary bread."
Although the decree was issued under the aegis of the Sacred Congregation of the Discipline of the Sacraments, I believe that Pius X wrote it, because its writing style mirrors that of the pope's own letters; in any case, he approved it. What I find particularly striking is how he rails with visible anger against those who would deprive children of the Eucharist:
[The] practice of preventing the faithful from receiving on the plea of safeguarding the august Sacrament has been the cause of many evils. It happened that children in their innocence were forced away from the embrace of Christ and deprived of the food of their interior life; and from this it also happened that in their youth, destitute of this strong help, surrounded by so many temptations, they lost their innocence and fell into vicious habits even before tasting of the Sacred Mysteries. And even if a thorough instruction and a careful Sacramental Confession should precede Holy Communion, which does not everywhere occur, still the loss of first innocence is always to be deplored and might have been avoided by reception of the Eucharist in more tender years.Here we have a pope effectively saying that depriving children of "the food of their interior life" is an abuse. It is a spiritual abuse, forcing children "away from the embrace of Christ," and increasing the risk that they will be prey to those who seek to tempt them.
As members of the baptized, our identity is as adopted sons and daughters of Christ. To approach the Eucharistic table therefore is to recognize one's identity as an individual, a moral actor, a person with inestimable dignity as a child of God. Those who force children away from the Eucharist deny them their dignity. It is a profound message, and the fact that Pius X put it forth at a time when children had few advocates makes him an especially appropriate patron for those seeking to heal, or help others heal, from childhood wounds.
Read more about My Peace I Give You at the Patheos Book Club.