Although the problem of steelmaking from P-containing irons, which requires a basic slag, was solved around 1880 by the discovery that it could be carried out in converters lined with calcined dolomite or magnesite and in open-hearth furnaces having hearths of the same materials, it was not until the 1930s that a basic refractory, chrome-magnesite, capable of replacing silica in open-hearth roofs was produced. Investigational approaches which identified the causes of such limitations in use and led to the development of basic refractories, including magnesia-carbon, capable of meeting the demands of the new steelmaking processes, will be described and possible directions of further development suggested.