From Middle English and Old English lower case letter a and split of Middle English and Old English lower case letter æ.
:* File:Rune-Ac.png|10px|Anglo-Saxon Futhorc letter ᚪ Old English lower case letter a from 7th century replacement by Latin lower case letter a of the Anglo-Saxon Futhorc letter ᚪ, derived from Runic letter ᚫ.
:* File:Rune-Æsc.png|10px|Anglo-Saxon Futhorc letter ᚫ Old English lower case letter æ from 7th century replacement by Latin lower case ligature æ of the Anglo-Saxon Futhorc letter ᚫ, also derived from Runic letter ᚫ.
From Middle English a, from Old English ān. The "n" was gradually lost before consonants in almost all dialects by the 15th century.
From Middle English a, o, from Old English a-, an, on.