Father Jan Cieplak was auxiliary bishop of the Mogilev archdiocese, at that time the largest Roman Catholic archdiocese in the world, covering the whole of Russia up to Sakhalin.

The Polish-Bolshevik war broke out on 14 February 1919. The site of the first confrontation was the town of Mosty near Szczuczyn in the Grodno region, where Polish Army units halted the Red Army’s march.