According to the Arda Viraf, I, 2, Zoroaster taught, in round numbers, some 300 years before the invasion of Alexander.
Lately operating in the Rhodope came up, some by the Arda and some via Demotika on the S.
Front (left bank of the Tunja), was an advanced position, or rather a discontinuous series of field positions on selected sites astride the saddles of ground which separate the rivers (Tunja and lower Maritsa, Maritsa and Arda, Arda and upper Maritsa, upper Maritsa and Tunja).
Between Arda and lower Maritsa and the i 1th with part of the 2nd in the broadest sector, the eastern.
Each side extended southward in search of the other's flank till the Arda was approached.