 In the Old Polish, nasal vowels were either not indicated at all or indicated with digraphs including a nasal consonant, letter Ø was also used.During the first decades after the introduction of movable type to Poland (exclusively blackletter at the time) a need to standardize orthography developed, and in early 16th century Stanisław Zaborowski, inspired by Old Czech orthography reform by Jan Hus, analyzed Polish phonology and in a book which became very popular proposed to add diacritics to Polish, including to mark nasal vowels with strokes.In particular, he proposed to write /ɛ̃/ as "a" with "semivirgula superior" (the letter was used to spell the phoneme traditionally because it was the original medieval pronunciation, see below), which printers of the time found not very convenient, and instead, Hieronymus Vietor crossed the lower part of an "e".