 Rosenberger's father had a clothing store in Austria and he was interested in fabrics from a very early age.Rosenberger was approached by Moshe Neuman to find out how to best check garments for shatnes, a biblically forbidden mixture of wool and linen according to Jewish law.Rosenberger sought out garment dealers in both Williamsburg and the Lower East Side of Manhattan but found that there was both little knowledge and little interest in this area of Jewish law.