The first Doab ("country between two rivers"), lying between the Indus and the Jelum, is 147 miles in breadth; this Doab is intersected with defiles and mountain chains, and covered with thickets. It is the worst cultivated, the most barren and thinly peopled of all the Doabs. The second Doab is formed by the rivers Jelum and Chenāb. At its narrowest breadth it is forty-six miles across; this country is flat, except the low range of hills terminating the beds of rock salt that run through the Jelum. It is capable of very improved cultivation. The third Doab lies between the Chenāb and the Rāvee. This Doab might with the greatest ease be converted into a most fertile country, were the land irrigated by the mountain streams, which could be conveyed in artificial canals. It is seventy-six miles in breadth at its widest part. The fourth Doab is considerably the smallest, being only forty-four miles in breadth. It, however, comprises some of the most important cities, namely, Lahore, Umritsur and Kussoor. It lies between the Rāvee and the Sutlej. Besides this fine country, the rule of the Sikhs at this time extended over the rich Province of Mooltan, on the right bank of the Indus. The territory under the sway of the Maharajah might be estimated at 8,000 geographical square miles, with a population of about 5,000,000 inhabitants, and an annual revenue of between £2,000,000 and £3,000,000 sterling. The Sikhs, or "Disciples," were originally a religious sect, which arose among the inhabitants of the Punjaub as late as the close of the fifteenth century. Their leader was Nānak, who succeeded in drawing thousands of enthusiasts after him. He was a disciple of Kahir, and consequently a Hindoo deist; he upheld the principle of universal toleration, calling upon his followers to worship the one invisible God, and to lead a virtuous life. He died at the age of seventy, in 1539. His doctrines and writings tended greatly to elevate the mind, and reform the morals of his disciples. The Sikhs believe that the soul of Nānak has transmigrated into the body of each succeeding Gooroo, or teacher. The spirit of religious toleration adopted by the Sikhs, was odious in the eyes of the bigoted Mahomedans, and Arjoon, their chief, who was celebrated not only for his piety, but for his wisdom and skill as a legislator, was falsely accused, and put to death, by the Mogul, in 1606. Arjoon converted the obscure hamlet of Umritsur into a city of great importance, by making it the seat of his disciples, and the place of the Sikhs' pilgrimage. His cruel death transformed the quiet and peaceable Sikhs into a warlike nation; their spirit was roused, and, led on by Hur Govind, the son of their murdered priest, they determined to avenge themselves upon his assassins. The Mogul, however, was too mighty for them; and they were forced to retreat into the mountain districts beyond Lahore.