Next day we forded a branch of the Zab, and entered the valley of this great confluent of the Tigris, its principal source being but a few miles to the north of us, near the frontiers of Persia. The land is so heavy, that the rude plough of the country requires frequently as many as eight pairs of oxen. The Armenian ploughmen sit on the yokes, and whilst guiding or urging the beasts with a long iron-pointed goad, chant a monotonous ditty to which the animals appear so well accustomed, that when the driver ceases from his dirge, they also stop from their labors. A dell near our path was pointed out to me as the spot where the unfortunate traveller Schulz was murdered by Nur Ullah Bey, the Kurdish chief of Hakkiari. Turning up a narrow valley towards the high mountains, we suddenly came in sight of the castle of Bash-Kalah, one of the ancient strongholds of Kurdistan. Its position is remarkably picturesque. It stands on a lofty rock, jutting out from the mountains which rise in a perpendicular wall behind it. At the foot are grouped the houses of a village. I found Izzet Pasha encamped at a considerable elevation in the rocky ravine[161], which we reached, guided by cawasses carrying huge glass lanterns, by a very precipitous and difficult track. I remained with him until the night was far advanced, and then returned to our encampment. He informed me that there was a direct road from Bash-Kalah to Mosul of forty hours, through Beit-Shebbet, Daoudiyah, and Dohuk, which, with very little labor and expense, could be made practicable for guns. Bash-Kalah was formerly the dwelling-place of Nur Ullah Bey, a Kurdish chief well-known for his rapacious and blood-thirsty character, and as the murderer of Schulz. He joined Beder Khan Bey in the great massacres of the Nestorians, and for many years sorely vexed those Christians who were within his rule. After a long resistance to the troops of the Sultan, he was captured about two years before my visit, and banished for life to the island of Candia.