The history of the modern exploration of the Nile is closely associated with the history of Egypt in modern times. The men who first visited Egypt and ascended the Nile valley were in almost every case Indo-Euro-peans. The early Egyptians were familiar perhaps with the Nile as far as Khartum, and with the Blue Nile up to its source in Lake Tsana, but they showed little or no interest in exploring the White Nile. In 457 B.C., Herodotus entered Egypt, and ascended the Nile as far as the First Cataract. He then learned many things about its upper waters, and made enquiries about the territories which lay beyond. He heard that the source was unknown; that there was a centre of civilisation in a city of the Ethiopians, in the bend of the Nile at Meroe (Merawi of to-day), but about the regions beyond he was unable to learn anything. Eratosthenes, the earliest geographer of whom we have record, was born in 276 b. c. at Cyrene, North Africa. From the information he gathered and edited, he sketched a nearly correct route of the Nile to Khartum. He also inserted the two Abyssinian affluents, and suggested that lakes were the source of the river. When Rome extended her domains over Egypt, in 30 B.C., the interest of the Romans was aroused in the solution of the problem of the discovery of the source of the Nile. Strabo set out with AElius Gallus, the Roman Governor of Egypt, on a journey of exploration up the Nile as far as Philae, at the First Cataract. About 30 B.C. Greek explorers by the names of Bion, Dalion, and Si-mondes were engaged in active exploration of the Nile above the First Cataract and perhaps south of Khartum, according to the account of Pliny the Elder, writing in 50 A.D. The Emperor Nero, in A.D. 66, sent an expedition up the Nile, and its members journeyed as far as the modern Fashoda and perhaps even beyond the White Nile. Their advance was impeded by the sudd, and, after writing discouraging reports, their attempt was abandoned. Among the Greek merchants who traded on the East African coast was one named Diogenes, who had been informed by an Arab that by a twenty-five days' journey one could gain access to a chain of great lakes, two of which were the headwaters of the White Nile. They also said that there was a mountain range, named from its brilliant appearance the Mountains of the Moon. He was informed that the Nile formed from the two head streams, flowed through marshes until it united with the Blue Nile, and then it flowed on until it entered into well-known regions. Diogenes reported this to a Syrian geographer named Marinus of Tyre, who wrote of it in his _Geography_ during the first century of the Christian era. The writings of Marinus disappeared, it is supposed, when the Alexandrian Library was scattered, but luckily Gladius Ptolemy quoted them, and thus they have been preserved for us. Ptolemy wrote, in 150 A.D., the first clearly intelligible account of the origin of the White Nile, the two lakes,