from the Third Cataract in the north to Soba, near present-day Khartoum, in the south. An Egyptian-influenced pharaonic tradition persisted among a line of rulers at Meroë, who raised stelae to record the achievements of their reigns and erected Nubian pyramids to contain their tombs. These objects and the ruins of palaces, temples, and baths at Meroë attest to a centralized political system that employed artisans' skills and commanded the labour of a large work force. A well-managed irrigation system allowed the area to support a higher population density than was possible during later periods. By the first century BC, the use of Egyptian hieroglyphs gave way to a Meroitic alphabet adapted for the Nubian-related language spoken by the region's people. Meroë's succession system was not necessarily hereditary; the matrilineal royal family member deemed most worthy often became king. The kandake or queen mother's role in the selection process was crucial to a smooth succession. The crown appears to have passed from brother to brother (or sister) and only when no siblings remained from father to son. Although Napata remained Meroë's religious centre, northern Kush eventually fell into disorder as it came under pressure from the Blemmyes, predatory nomads from east of the Nile. However, the Nile continued to give the region access to the Mediterranean world. Additionally, Meroë maintained contact with Arab and Indian traders along the Red Sea coast and incorporated Hellenistic and Indian cultural influences into its daily life. Inconclusive evidence suggests that metallurgical technology may have been transmitted westward across the savanna belt to West Africa from Meroë's iron smelteries. Relations between Meroë and Egypt were not always peaceful. As a response to Meroë's incursions into Upper Egypt, a Roman army moved south and razed Napata in 23 BC. The Roman commander quickly abandoned the area, however, deeming it too poor to warrant colonization. In the second century AD, the Nobatia occupied the Nile's west bank in northern Kush. They are believed to have been one of several well-armed bands of horse- and camel-borne warriors who sold their skills to Meroë for protection; eventually they intermarried and established themselves among the Meroitic people as a military aristocracy. Until nearly the fifth century, Rome subsidized the Nobatia and used Meroë as a buffer between Egypt and the Blemmyes. Meanwhile, the old Meroitic kingdom contracted because of the expansion of the powerful Kingdom of Aksum to the east.