Three dynasties ruled over Egypt during
the era of the New Kingdom, probably the most powerful and prosperous of
the great bureaucratic states of Ancient Egypt. These dynasties represent
a series of distinct phases in which the power of the state rose, flourished,
and then declined. The Eighteenth Dynasty saw several reigns devoted to
the stabilization of the state's control over the Nile Valley (including
that of Queen Hatshepsut) and then burst forth in a wave of imperial conquests
under the leadership of Tuthmosis III (circa 1450 AD). Tuthmosis III created
an empire that controlled much of modern Palestine and Lebanon, and the
booty won by his conquests earned great renown and wealth for the state.
His immediate successors were probably the wealthiestand certainly the most
profligate of all of those who ever ruled Ancient Egypt, a fact marked not
only by their magnificent tombs but by the construction of such massive
structures as the Luxor Temple (most of which was completed during the reign
of Tuthmosis III's great-grandson, Amunhotep III circa 1400 BC). But over
several
generations,
Tuthmosis III's successors allowed the state's control over its far-flung
possessions to weaken, and during the controversial reign of Amunhotep III's
son, Akhnaten (1377-1360), Egypt's empire collapsed. Within a generation,
the Eighteenth Dynasty was replaced by a new ruling family, the Nineteenth.
Under the leadership of its greatest kings, Seti I (circa 1300) and his
son Rameses 11 (circa 1275), the Nineteenth Dynasty regained some of the
territories won a century-and-a-half earlier by Tuthmosis lilt But Egypt's
hold on its Eastern empire was precarious. Powerful new opponents threatened
Egypt's intereststhe Hittite Empire, for example, which, from its base in
Anatolia, created a huge state that dominated much of the Fertile Crescent.
By 1200 BC, Egypt had once again lost most of its Asiatic possessions, and
the Nineteenth Dynasty itself came to its end in the form of a series of
weak rulers. A new dynasty replaced it, the Twentieth, but its greatest
king, Rameses 111, spent most of his reign warding off invaders who attacked
the Nile Valley itself. The walls of his mortuary temple at Madinat Habu
in the Luxor area record in detail victories over invading "Libyans"
(attackers from the West) and a coalition of sea-borne invaders grouped
under the name "the Sea Peoples".)

At its height, the New Kingdom was an era
of astonishing achievement in art and architecture most dramatically marked
at Wasetmodern Luxor (or "Thebes", as the Greeks called it, probably
a Greek corruption of an Egyptian term).). Since the Luxor area was the
origin-point of the New Kingdom state, the kings of the Eighteenth, Nineteenth,
and Twentieth Dynasties turned it into the ritual and ceremonial heart of
the state. Here they built enormous shrines to the chief god of the state
cult, Amun, whose continuing prominence was still due to luckthat is, to
the fact that the Seventh and Eighteenth Dynasties hailed from the locality
where he was the great regional deity. Thus Karnak, the center of the cult
of Amun, became the largest and most impressive temple complex in the world.
The New Kingdom kings also built tombs for themselves in the Luxor areamagnificent
shaft-tombs that were carved into the walls of the Valley of the Kings.
Grand mortuary temples were also built, funerary palaces where the kings'
spirits could be served throughout eternity. These monuments gave visual
expression to the power of the state itself, in much the same way that the
great pyramid complexes had testified to the grandeur of the Old Kingdom
state a thousand years earlier. But in spite of its magnificence, Luxor
was not the true "capital" of the state, for the kings resided
most of the time either in the Memphis area in the north or in palace cities
built on the eastern edge of the Delta, from which their armies had easy
access to the deserts leading to Asia. Luxor was thus a shrine center of
great ceremonial importance to the New Kingdom state. 
A constant theme of New Kingdom history is the growing political power of the cult of Amun. This power derived from the support that the state itself was devoting to the cult, granting it lands and territories and the income that these possessions generated. In return, the state received the benefits of the cult's ideological support, allowing it to claim that the power of the reigning king was a direct grant from Amun. Some scholars have argued that the cult and its servants the priests of Amun, who controlled and manipulated the cult's resources benefited from this arrangement far more than did the state, since the growing independent economic power of the cult turned it into a major political force. It has also been suggested that, at the end of the Eighteenth Dynasty, Amunhotep 111 and his son Akhnaten attempted to strike at the political power of the Amun cult by depriving it of its economic base: they tried to shift the state's patronage to another cult, a revived version of the old royal solar cult in which the king and the all-powerful sun were equated. This effort ultimately failed, and during the reign of Akhnaten's successor, Tutankhamun, the primacy of the state cult of Amun was restored.
But was the cult of Amun in fact a threat to the New Kingdom state? Except for the events associated with the reign of Akhnaten, the evidence for this is poor, consisting principally of the fact that when the New Kingdom state collapsed around 1100 BC, its successor in Upper Egypt was a dynasty of priests of Amun, and that these clerical dynasts ruled the South more-or-less independently of the XXIst Dynasty kings who governed the North. However, the available evidence suggests that the priests in question were in fact of the same family as the rulers of the XXIst Dynasty, and one might reasonably conclude that the "division" of authority was simply a practical administrative rearrangement . For the decline of the New Kingdom state was probably due not to a struggle between priests and kings but instead to the intense pressure that constant threats from outside of Egypt placed upon the its stability threats which disastrously drained its resources. It is likely that, throughout this era of crisis, the cult of Amun conscientiously played out its role as a key support of the state. But when the kings of the XXIst Dynasty finally accepted the fact that they could no longer maintain control over all of the Nile Valley with the limited resources available to them, they seem to have willingly ceded authority in the South to their relatives, the high priests of Amun.