On [[December 10]], 1863, he transferred his obedience as a novice to the St. Simeon Stavropighial Monastery in Moscow. There, he continued his labors with Christian humility. On [[December 23]], he as blessed to wear an [[altar]] server’s robe. Soon was appointed sacristan in the temple with obedience to keep the church and its vessels clean and to dust and remove all rubbish.
In 1866, Nicholas was appointed secretary to [[Archimandrite]] Gury who was assigned [[rector]] of the Russian ambassadorial church in Rome. On [[February 17]], 1866, Nicholas was [[tonsure]]d a [[monk]] with the name Flavian. On [February 18
[[, he was [[ordination|ordained]] hiero[[deacon]]. Soon, however, relations between the Russian government and the papal court were broken and Archimandrite Gury and hierodeacon Flavian were sent to Kazan via Naples, where Archimandrite Gury had been appointed to the faculty of the [[Kazan Theological Academy|Kazan Theological Seminary]] under [[Bishop]] Cheboksark, while Dn. Flavian was assigned to one of the local monasteries. On [[April 9]], 1867, Dn. Flavian was ordained a hieromonk. On [[February 15]], 1868, hieromonk Flavian was assigned to a Simferopol [[monastery]] where he taught classes in church law and other subjects.
On [[June 6]], 1873, Fr. Flavian was assigned as a member of the Russian Orthodox Mission in Beijing, China. At the time the mission was restrained from active evangelism and functioned as a semi-diplomatic station between the Chinese and Russian governments. For the next ten years Fr. Flavian engrossed himself in the missionary service at the mission. He eagerly, learned both spoken and written Chinese language. He then continued the work of translating the prayer and service books into Chinese as well as collecting and editing the documents that had been translated previously. Additionally, he produced documents useful in the business affairs of the mission.