37 We therefore consider it very opportune that through this solemn centenary celebration, under your guidance, the extremely close union of this outstanding martyr with the Holy See and his extraordinary accomplishments be shown in their full splendor; this will confirm the faith and loyalty of those who cling to the infallible Teaching Authority of the Roman Pontiffs, and it cannot help but arouse to salutary and deeper reconsideration those who for any reason whatsoever have been separated from the successors of Blessed Peter, and summon them, with the help of divine grace, to undertake deliberately and courageously that journey which would lead them happily back to the unity of the church. This is what We exceedingly long for and in suppliant prayer earnestly beg of the Giver of celestial gifts, namely, that the ardent desire of all good men be at last fulfilled, that all may be one and all return to the unity of the fold, to be fed by a single Shepherd.
Source: Ecclesiae Fastos (Vatican.va)