The Battle of Pelusium was the first major battle between the Achaemenid Empire and Egypt. This decisive battle transferred the throne of the Pharaohs to Cambyses II of Persia, marking the beginning of the Achaemenid Twenty-seventh Dynasty of Egypt. It was fought near Pelusium, an important city in the eastern extremes of Egypt's Nile Delta, 30 km to the southeast of the modern Port Said, in 525 BCE. The battle was preceded and followed by sieges at Gaza and Memphis.