The Twenty-Eighth Dynasty is often combined with other groupings of rulers of ancient Egypt under the title, Late Period. These other groupings include the Twenty-Sixth, Twenty-Seventh, Twenty-Ninth, Thirtieth, and Thirty-First dynasties

The Twenty-Eighth Dynasty of Egypt had one ruler, Amyrtaeus, who was a descendant of the Saite kings of the Twenty-Sixth Dynasty, and led a successful revolt against the Persians on the death of Darius II. No monuments of his reign have been found, and little is known of his reign.

Amyrtaeus (or Amenirdisu) of Sais is the only king of the Twenty-eighth dynasty of Egypt and is thought to be related to the royal family of the Twenty-sixth dynasty. He ended the First Persian Occupation and reigned from 404 BC to 399 BC.

Amyrtaeus was probably the grandson of the Amyrtaeus of Sais who is known to have carried on a rebellion in 465 - 463 BC with the Libyan chief, Inarus (himself a grandson of Psamtik III), against the Satrap of Artaxerxes I. He is known from Aramaic and ancient Greek sources, and is mentioned in the Demotic Chronicle. He is not known to have left any monuments, and his name in Egyptian is only reconstructed from demotic notices.

Before assuming the throne of Egypt, Amyrtaeus had revolted against Darius II as early as 411 BC, leading a guerrilla action in the western Nile Delta around his home city of Sais. Following the death of Darius, Amyrtaeus declared himself king in 404 BC. According to Isocrates, Artaxerxes II assembled an army in Phoenicia under the command of Abrocomas to retake Egypt shortly after coming to the Persian throne, but political problems with his brother Cyrus the Younger prevented this from taking place, allowing the Egyptians sufficient time to throw off Achaemenid rule. While the rule of Amyrtaeus in the western Delta was established by 404 BC, Artaxerxes II continued to be recognized as king at Elephantine as late as 401 BC, but Aramaic papyri from the site refer to Regnal Year 5 of Amyrtaeus in September 400 BC. The Elephantine papyri also demonstrate that between 404 and 400 BC (or even 398) Upper Egypt remained under Persian control, while the forces of Amyrtaeus dominated the Delta.

Amyrtaeus was defeated in open battle by his successor, Nepherites I of Mendes, and executed at Memphis, an event which the Aramaic papyrus Brooklyn 13 implies occurred in October 399 BC.