the Attic–Ionic vowel shift. In a few cases, the long close-mid vowels developed from monophthongization of the pre-Classical falling diphthongs . In most cases, they arose through compensatory lengthening of the short vowels or through contraction. In both Aeolic and Doric, Proto-Greek did not shift to . In some dialects of Doric, such as Laconian and Cretan, contraction and compensatory lengthening resulted in open-mid vowels , and in others they resulted in the close-mid . Sometimes the Doric dialects using the open-mid vowels are called Severer, and the ones using the close-mid vowels are called Milder. Diphthongs Attic had many diphthongs, all falling diphthongs with as the second semivocalic element, and either with a short or long first element. Diphthongs with a short first element are sometimes called "proper diphthongs", while diphthongs with a long first element are sometimes called "improper diphthongs." Whether they have a long or a short first element, all diphthongs count as two morae when applying the accent rules, like long vowels, except for in certain cases. Overall Attic and Koine show a pattern of monophthongization: they tend to change diphthongs to single vowels. The most common diphthongs were and . The long diphthongs occurred rarely. The diphthongs changed to in the early Classical period in most cases, but remained before vowels. In the tables below, the diphthongs that were monophthongized in most cases are preceded by an asterisk, and the rarer diphthongs are in parentheses. The second element of a diphthong was often pronounced as a doubled semivowel or before vowels, and in other cases it was often lost: ('Athenians'): ('I do'): either or Doric : Attic : ('I command'): ('sign'): The diphthong merged with the long close front rounded vowel in Koine. It likely first became . Change to would be assimilation: the back vowel becoming front because of the following front vowel . This may have been the pronunciation in Classical Attic. Later it must have become , parallel to the monophthongization of , and then , but when words with were borrowed into Latin, the Greek digraph was represented with the Latin digraph , representing the diphthong . Thucydides reports the confusion of two words (2:54), which makes more sense if was pronounced : ('plague'): possibly ('famine'): In the diphthongs , the offglide became a consonant in Koine Greek, and they became Modern Greek . The long diphthongs lost their offglide and