its successful completion. Necho's war with Nebuchadnezzar II most probably prevented the canal's continuation. Necho's project was completed by Darius I of Persia, who ruled over Ancient Egypt after it had been conquered by his predecessor Cambyses II. It may be that by Darius's time a natural waterway passage which had existed between the Heroopolite Gulf and the Red Sea in the vicinity of the Egyptian town of Shaluf (alt. Chalouf or Shaloof), located just south of the Great Bitter Lake, had become so blocked with silt that Darius needed to clear it out so as to allow navigation once again. According to Herodotus, Darius's canal was wide enough that two triremes could pass each other with oars extended, and required four days to traverse. Darius commemorated his achievement with a number of granite stelae that he set up on the Nile bank, including one near Kabret, and a further one a few kilometres north of Suez. Darius the Great's Suez Inscriptions read: The canal left the Nile at Bubastis. An inscription on a pillar at Pithom records that in 270 or 269 BCE, it was again reopened, by Ptolemy II Philadelphus. In Arsinoe, Ptolemy constructed a navigable lock, with sluices, at the Heroopolite Gulf of the Red Sea, which allowed the passage of vessels but prevented salt water from the Red Sea from mingling with the fresh water in the canal. In the second half of the 19th century, French cartographers discovered the remnants of an ancient north–south canal past the east side of Lake Timsah and ending near the north end of the Great Bitter Lake. This proved to be the canal made by Darius I, as his stele commemorating its construction was found at the site. (This ancient, second canal may have followed a course along the shoreline of the Red Sea when it once extended north to Lake Timsah.) Receding Red Sea and the dwindling Nile The Red Sea is believed by some historians to have gradually receded over the centuries, its coastline slowly moving southward away from Lake Timsah and the Great Bitter Lake. Coupled with persistent accumulations of Nile silt, maintenance and repair of Ptolemy's canal became increasingly cumbersome over each passing century. Two hundred years after the construction of Ptolemy's canal, Cleopatra seems to have had no west–east waterway passage, because the Pelusiac branch of the Nile, which fed Ptolemy's west–east canal, had