From the Gesta Henrici Quinti:
Sed Gallorum nobilitas quae plena fronte prius accesserat, ut de prope conjunctionem venerat, vel timore telorum, quorum adversitas eos reptabat per latera et umbracula cassidum, vel ut citius penetrarent nostram fortitudinem ad vexilla, diviserunt se in tres turmas, invadentes bellum nostrum in tribus locis ubi erant vexilla: et in prima mixtione lancearum tam feroci impetus grassati sunt nostros, quod eos fere ad longitudinem lanceae retrocedere compulerunt.
Here is Anne Curry's translation in The Battle of Agincourt Sources and Interpretations:
But the French nobility who had previously advanced in line abreast and all but come to grips with us, either from fear of the missiles which by their very force pierced the sides and visors of their helmets, or in order the sooner to break through our strongest points and reach the standards, divided into three columns, attacking our line of battle at the three places where our standards were. And in the melee of spears which then followed, they hurled themselves against our men in such a fierce charge as to force them to fall back almost a spear's length.