Kirk's Original Coco Castile Bar Soap Since 1839, Kirk's Original Coco Castile Soap has given the consumer a high quality, natural soap at an affordable price. "Castile" originally referred to the highly-prized vegetable based soap produced in Castile, Spain. For centuries this soap was considered "the soap of royalty" because of its luxurious lather and gentleness to the skin. Today, "Castile" refers to any vegetable based soap.