Psammetikhos I was the first ruler of the 26th Dynasty, though his reign overlaps that of the 25th Dynasty. We believe he ruled from about 664 through 610 BC. This is often referred to as the Saite period in Egyptian history, named for the power center of the Delta.   It was not until Psammetikhos' ninth regnal year that he completely control Egypt. His birth name was Psamtik I, but he was known as Psammetichus I by the Greeks.  His thrown name was Wah-ib-re, meaning "Constant is the Heart of Re" (Horus Name: Aib, Nebty Name: Neba, Bik-nub Name: Qenu). 

Some Egyptologists place the 26th Dynasty in to Third Intermediate Period of Egypt's history, while others place it in the Late Period.  Certainly, when Psammetikhos began his rule of Egypt, things were still chaotic, with various rulers claiming power. But Psammetikhos would consolidate his rule over Egypt, and reign for about a half a century, returning Egypt to stability. 

Both Psammetikhos I and his father, Necho I of Sais were originally involved with an intrigue associated with the Kushite ruler, Taharqo against Assyria, but were then captured, held and indoctrinated by the Assyrians. Psammetikhos I was even given the Assyrian name, Nabu-shezibanni, before finally being returned to Egypt where his father assumed power in the Delta.

Upon the death of Necho in 664, Psammetikhos was recognized by his Assyrian overlords as King of Egypt, but this was a title at first without substance.  He had rule over Memphis and Sais, but mostly the country was controlled by the old advisories of the Nubian Kings, who had been driven back to their own land. His was tasked with the responsibilities of controlling not only the unruly princes and petty kings of the Delta, but also to reconcile with the power center at Thebes.  

Working with Thebes turned out to be easier then one might imagine, because he was able to align himself with the daughter of a great Theaban nobleman named Mentuemhet.  At that time, she held the title, "Adoratice of Amun" (God's Wife of Amun). He was able to insert his own daughter, Nitokris,  as her successor He was therefor able to effect both secular and religious ties that were to hold his growing presence in Egypt together, while he went after his Delta opponents.  In order to do this, he raised a conscript army, as well as employing the services of mercenaries, many of whom were Greek, including Carians.  This involvement with foreign mercenaries apparently caused some concern about their control within Egypt, and archaeological evidence suggests that sites such as Naukratis, among others, were established to facilitate this, along with offering Egypt an increased commercial presence within the Mediterranean world. 

Psammetikhos also took as his principle wife Mehtemweskhet who was the daughter of Harsiese S, High Priest at Heliopolis, further cementing his rule. 

To all appearances, Psammetikhos I had been a loyal subject of his Assyrian overlords, but as that empire's glories waned, Psammetikhos took his opportunity to break their hold, and in so doing became the absolute ruler of Egypt.

During the remaining four decades of Psammetikhos I's rule, he continued to consolidate his power and bring the country under complete unity, something Egypt had really not seen in a number of years.  He undertook a number of building projects, including fortresses in the Delta at Naukratis and Daphnae, as well as at Elephantine.  He also greatly expanded the Serapeum at Saqqara.  

After consolidating Egypt, militarily, Psammetikhos I was mostly concerned with keeping Egypt's sovereignty strong. There were expeditions into northern Nubia probably to discourage any further ambitions of the Kushite kings. In the north east, Babylon had become such an important power that the king actually formed an alliance with his old masters in Assyria in order to combat Babylon's growing menace. This enabled Egypt to obtain control of the Palestinian coast.  There were also actions required on the Libyan frontier in order to combat the threat posed by the fugitive Delta princes.

Psammetikhos I, as well as other kings of this dynasty, followed the archaistic tendencies of the previous dynasty in art, as well as in many customs, such as the formulation of their names.  The renaissance in art is such that it is sometimes difficult to tell whether an artifact came from this period of time, or from the Old or Middle Kingdoms.

Psammetikhos I was succeeded by his son, Necho (Nekau) II, who continued to build on his father's accomplishments in Egypt.