The Pope considered that allowing the Tridentine Mass to those who request it was a means to prevent or heal schism, stating that, on occasions in history, "not enough was done by the Church's leaders to maintain or regain reconciliation and unity" and that this "imposes an obligation on us today: to make every effort to enable for all those who truly desire unity to remain in that unity or to attain it anew." Many feel the decree aimed at ending the schism between the Holy See and traditionalist groups such as the Society of Saint Pius X (SSPX). Cardinal Darío Castrillón Hoyos, the president of the Pontifical Commission established for the purpose of facilitating full ecclesial communion of those associated with that Society, stated that the decree "opened the door for their return". Bishop Bernard Fellay, superior general of the SSPX, expressed "deep gratitude to the Sovereign Pontiff for this great spiritual benefit".