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In the Russian language to the reform of the 1918 letter I, ¯ (later wrote with a point - i) was used in much the same as in the Old Church language, namely:

before vowels and before h (istorіya, russkіy, Іerusalim);
in a word mіr within the meaning of "Universe," "society" to distinguish it from the word mir in the sense of "calm."
Exception to pre-reform spelling words were difficult, which ended in the first part and on: pyatiugolnik, naiuzhasny.

At the beginning of words between vowels and the letter of I sometimes pronounced as a consonant [d] іod, maіor (as in modern words that begin and before a vowel).

In the early civil font number of points over st was not permanent, but in 1738 it was determined in the usual way: the capital letter is written without dots, lowercase - with one point, when you add the same stress this point usually disappears. Later, however, for still quite a long time, letter ¯ continued to be used with two points (this spelling was used until the beginning of the XIX century).