A group of 13 strains was isolated from samples of biofilm formation on the mural paintings of the Servilia tomb (necropolis of Carmona, Spain) and the Saint-Catherine chapel (castle at Herberstein, Austria). The strains were subjected to a polyphasic taxonomic study, including (GTG)5-PCR, 16S rDNA sequence analysis, DNA-DNA hybridizations, DNA base ratio determination, analysis of fatty acids, polar lipids and menaquinones and morphological and biochemical characterization. In a phylogenetic tree based on neighbour-joining of 16S rDNA sequences, the strains are divided in two major groups, representing three novel species according to DNA-DNA relatedness, that are positioned at approximately equal distances from Virgibacillus and Salibacillus. After comparison of the novel results with existing data, the transfer of the species of Salibacillus to Virgibacillus is proposed, with the resulting new combinations Virgibacillus marismortui comb. nov. and Virgibacillus salexigens comb. nov. Additionally, three novel species are described, for which the names Virgibacillus carmonensis sp. nov., Virgibacillus necropolis sp. nov. and Virgibacillus picturae sp. nov. are proposed. The respective type strains are LMG 20964T (=DSM 14868T), LMG 19488T (=DSM 14866T) and LMG 19492T (= DSM 14867T). Finally, an emended description of the genus Virgibacillus is given.