One hundred and forty-nine years ago on this day, March 6, the Congregation of Bishops and Regulars issued a decree, which begins, (in Latin) ... "Certain priests of the Congregation of the Most Holy Redeemer in the United States ... " (Well, it really begins, "Recently certain [priests]" etc.) By this decree, Fr. Isaac Hecker and his four American companions, namely Clarence Walworth, Augustine Hewit, George Deshon, and Francis Baker, were released from their vows in the Congregation of the Most Holy Redeemer (the Redemptorists). In the next few months they organized themselves under a rule (very similar to the Redemptorist rule formulated by St. Alphonsus Liguori), and founded the Missionary Society of St. Paul the Apostle.
March 6 is regarded as the "birthday" if you will, of the Paulist Fathers.
Next year, the anniversary of Nuper nonnulli will mark the one hundred and fifteeth anniversary of the Society.
The 150th Anniversary celebrations website.
Oh, and most interestingly, Fr. Walter Elliott CSPs famous Life of Father Hecker is available online for free. (It was the French translation of Fr. Elliott's book that lead to the whole Americanism controversy, but that's a tale for another day ... )