The iota subscript is today considered an obligatory feature in the spelling of ancient Greek, but its usage is subject to some variation. In some modern editions of classical texts, the original pronunciation of long diphthongs is represented by the use of iota adscript, with accents and breathing marks placed on the first vowel. The same is generally true for works dealing with epigraphy, paleography or other philological contexts where adherence to original historical spellings and linguistic correctness is considered important.