A letter written around 900 by Archbishop Theotmar of Salzburg (r. 873–907) and his suffragan bishops mentions that the pope sent Wiching to "a newly baptized people" whom Svatopluk "had defeated in war and converted from paganism to Christianity". Other sources also prove that Svatopluk significantly expanded the borders of his realm. For instance, according to the "Life of Methodius", Moravia "began to expand much more into all lands and to defeat its enemies successfully" in the period beginning around 874. The same source writes of a "very powerful pagan prince settled on the Vistula" in present-day Poland who persecuted the Christians in his country, but was attacked and seized by Svatopluk.