Corpus of Electronic Texts Edition
The Wooing of Emer by Cú Chulainn (Author: [unknown])

paragraph 29

Cuchulaind then repeated the conversation from the beginning to his charioteer, explaining it to him, to beguile the length of their way.‘By Intide Emna which I said when she asked me ‘whence hast thou come?’ I meant from Emain Macha. It is called Emain Macha from this, Macha the daughter of Sainreth Mac in Botha, wife of Crundchu, son of Agnomon, ran a race against two steeds of the king, after she had been forced to it by a strong injunction. She beat them, and bare a boy and a girl at one birth. And from those twins (emuin) is called, and from that Macha is named the plain of Macha.’