Great Moravia underwent considerable expansion in the 870s. For instance, the "Life of Methodius" refers to the capture of "a very powerful pagan prince settled on the Vistula" in territory of later Poland, and a letter written around 900 by Archbishop Theotmar of Salzburg states that Svatopluk conquered the region of Nitra, which had been thereto inhabited by pagans. Modern historiography, however, has tended to question the claims that huge neighboring territories were permanently annexed by Great Moravia. For instance, there is little clear archaeological or written evidence of a permanent extension of Moravian power in Lesser Poland or to the west in Silesia, or in Pannonia, as is suggested in earlier historical works.