Iota subscript is a 12-century invention. Rough and smooth breathings (ἁ for ha, ἀ for a) are much older Greek diacritics. For another example of classical dia

Iota subscript is a 12-century invention. Rough and smooth breathings (ἁ for ha, ἀ for a) are much older Greek diacritics. For another example of classical diacritics, see apices in Latin (á for long a).