The Brāhmī alphabet is the ancestor of most of the 40 or so modern Indian alphabets, and of a number of other alphabets, such as Khmer and Tibetan. It is thought to have been modelled on the Aramaic or Phoenician alphabets, and appeared in India sometime before 500 BC. Another theory is that Brāhmī developed from the Indus or Harappa script, which was used in the Indus valley until about 2,000 BC.
The earliest known inscriptions in the Brāhmī alphabet are those of King Asoka (c.270-232 BC), third monarch of the Mauryan dynasty.
Brāhmī was used to write a variety of languages, including Sanskrit and Prakrit.
Asokan Edict - Delhi Inscription
devānaṁpiye piyadasi lājā hevaṁ āhā ye atikaṁtaṁ
aṁtalaṁ lājāne husa hevaṁ ichisu kathaṁ jane
dhaṁmavaḍhiyā vāḍheya nocujane anulupāyā dhaṁmavaḍhiyā
vaḍhithā etaṁ devānaṁpiye piyadasi lājā hevaṁ āhā esame
huthā atākaṁtaṁ ca aṁtalaṁ hevaṁ ichisu lājāne katha jane
Thus spoke king Devanampiya Piyadasi: "Kings of the olden time have gone to heaven under these very desires. How then among mankind may religion (or growth in grace) be increased? Yea, through the conversion of the humbly-born shall religion increase"
Information about Brāhmī
The Edicts of King Asoka
ALPHABETUM - a Unicode font specifically designed for ancient scripts, including classical & medieval Latin, ancient Greek, Etruscan, Oscan, Umbrian, Faliscan, Messapic, Picene, Iberian, Celtiberian, Gothic, Runic, Old & Middle English, Hebrew, Sanskrit, Old Nordic, Ogham, Kharosthi, Glagolitic, Old Cyrillic, Phoenician, Avestan, Ugaritic, Linear B, Anatolian scripts, Coptic, Cypriot, Brahmi, Old Persian cuneiform: http://guindo.pntic.mec.es/~jmag0042/alphabet.html