Complex sentence: The close helmet was developed from the later versions of the sallet and the superficially similar armet in the late 15th century, and in contemporary sources was sometimes called an armet too, though modern scholarship draws a clear distincion between the two types.
Split into simpler sentences: The close helmet was developed from the later versions of the sallet and the superficially similar armet in the late 15th century. In contemporary sources it was sometimes also referred to an'armet', though modern scholarship draws a clear distinction between the two types.