On September 4 and 5, 1954, he was ordained hierodeacon and hieromonk by Archbishop Boris (Vik), Exarch of the Russian Patriarchate in Europe.
Published by St. Vladimir's Press, it urged the Orthodox Churches to adopt the Western Christian calculation of Easter, aka Paschalion.
Some critics of the book emphasized that only the Eastern Paschalion holds to the Nicene Council's 4th century prohibition on celebrating the resurrection before the Jewish Passover.
Some argued that abandonment of that stipulation could even imply a subtle subtext of antisemitism, since it would further decouple the connection between Christianity and Judaism.
Both during his episcopate and subsequent to his retirement, L'Huillier taught canon law at Saint Vladimir's Orthodox Theological Seminary.