Attic numerals were used by the ancient Greeks, possibly from the 7th century BC. They were also known as Herodianic numerals because they were first described in a 2nd-century manuscript by Herodian. They are also known as acrophonic numerals because the symbols derive from the first letters of the words that the symbols represent: five, ten,hundred, thousand and ten thousand. See Greek numerals and acrophony.

The use of Η for 100 reflects the early date of this numbering system: Η (Eta) in the early Attic alphabet represented the sound /h/. In later, "classical" Greek, with the adoption of the Ionic alphabet throughout the majority of Greece, the letter eta had come to represent the long e sound while the rough aspiration was no longer marked.^[1][2] It wasn't untilAristophanes of Byzantium introduced the various accent markings during the Hellenistic period that the spiritus asper began to represent /h/. Thus the word for a hundred would originally have been written ΗΕΚΑΤΟΝ, as compared to the now more familiar spellingἑκατόν. In modern Greek, the /h/ phoneme has disappeared altogether, but this has had no effect on the basic spelling.

Unlike the more familiar Modern Roman numeral system, the Attic system contains only additive forms. Thus, the number 4 is written ΙΙΙΙ, not ΙΠ.

The numerals representing 50, 500, and 5,000 were composites of pi (often in an old form, with a short right leg) and a tiny version of the applicable power of ten. For example,  is five times one thousand.

Specific numeral symbols were used to represent one drachma,^[3] to represent talents^[4] and staters,^[5] to represent ten mnas^[6] and to represent one half^[7] and one quarter.^[8]