Abstract
It was at one time almost universally believed, and is still believed by some scholars, that Thucydides cannot have written his account of the Pentekontaetia before his return from exile because he refers in it to the of Hellanicus, in which an event belonging to the year 407/6 was mentioned. This argument in favour of a late date for the composition of the excursus has been disputed and is now much less widely supported. It has been suggested that the reference to Hellanicus in 97. 2, or the whole of that section, was added by Thucydides to a part of his work written much earlier, or that an edition of the including an account of the Pentekontaetia may have been published long before 406 and the work have been subsequently continued