The Nubian king Piankhi (c. 741 BC – reigned c. 712) began his conquest of Lower Egypt, thus establishing the twenty-fifth or "Ethiopia" Pharaonic Dynasty. This is one of the few instances in African history where landlocked countries have played a role in Mediterranean politics.

Piankhi was the hereditary ruler of what is now the Upper Nile kingdom of Kush in northern Sudan. Around 741 BC he succeeded his father Kashta, who seems to have founded this Nubian kingdom. At this point, Lower Egypt had been in decline for nearly half a millennium. Infighting among small rulers is tearing the Egyptian state apart, so the time is ripe for a powerful invader. Piankhi marched steadily along the Nile, taking city after city. Around 721 BC he captured Heracleopolis and eventually Heliopolis in the delta.

At this point, Piankhi believed that the conquest of Egypt was complete, and he returned home to his Cushite capital in Napata after placing the Egyptian rulers in tributary status. He was received in Napata with much acclaim for having humiliated the former Egyptian overlords of Nubia, but the tributary states which he left soon fell under the sway of a local ruler named Tefnakht, who reasserted Egyptian independence

The details of the battle of Piankhi are well known, as he erected a huge stele at Amun with a long inscription. Modern Egyptologists regard this statement as unusually rational and vivid.

Like the Nubian rulers who followed him, Pianchi was culturally conservative and sought to strengthen some of Egypt's declining institutions. During his brief time in Lower Egypt, he oversaw the restoration of many destroyed temples. Returning to Kush, he introduced the Egyptian custom of building pyramids for royal tombs and built himself a huge pyramid at Kuru, south of Napata on the Nile. He rebuilt the temple at Jebel Barkal and also built many other temples in Egyptian style.

Strangely, all Egyptian sources mention Piankhi's love of fast horses. He introduced the practice of decorating cavalry to pull royal chariots, and the remains of a cavalry were found in his Kuru tomb