This set of files contains Supplementary Data associated with the emerging manuscript "Evolution upon leather manufacturing: comparison of the two Halobacterium salinarum strains isolated in the early 20-th century with the twin laboratory strains NRC-1 and R1." by Friedhelm Pfeiffer and Mike Dyall-Smith. The manuscript provides a detailed comparison of the complete genome sequences from four strains of Halobacterium salinarum: 91-R6 (NRC 34002, the type strain of Halobacterium salinarum); 63-R2 (NRC 34001, a strain originally reported as 'cutirubra'); NRC-1 and R1 (two laboratory strains). “Supplementary Methods” extends the Methods section of the manuscript, providing additional detail. “Supplementary Text S1” provides additional detail for the comparison of the chromosome from strain 63-R2 to those from strains NRC-1 and R1. “Supplementary Text S2” provides additional details for the comparison of the chromosomes from strains 63-R2 and 91-R6. “Supplementary Text S3” provides additional detail for the comparison of the plasmids from strain 63-R2 to those from strains NRC-1 and R1. “Supplementary Table S4” correlates positions from “core” sequences (devoid of strain-specific mobile genetic elements) to the original genome sequences.