Only highly-trained scribes could read hieroglyphic writing

He says they are nearly 4,000 years old, dating from around 1800 to 1900 BC.

Dr Darnell and his wife Deborah first found the letters in 1993, carved into soft limestone cliffs in a valley called Wadi el-Hol, beside an ancient road that linked Thebes and Abydos, west of present-day Luxor.

This summer the Darnells returned to Wadi el-Hol to research the inscriptions further, and Dr Darnell will present his findings next week at the annual meeting of the Society of Biblical Literature in Boston.

More democratic

Alphabetic writing emerged as a simpler and more democratic way of recording information than Egyptian hieroglyphics.

The first Semitic alphabet was developed from hieroglyphs

The letters are in a Semitic language, but Dr Darnell says they show a strong Egyptian influence.

He believes the letters may have been invented as a simplified version of an existing form of "cursive" or joined-up Egyptian pictographs, commonly used in ancient Egypt in graffiti.

Mercenaries

A number of experts agree that these inscriptions are the earliest alphabetic writing yet discovered and their location has forced a rethink on the origins of writing.

Up to now it has been believed that alphabetic writing was developed around 1600 BC - up to 300 years later than the Wadi el-Hol inscriptions - by Semitic people living in the Sinai Peninsula and further north in Syria and Palestine.

Scholars had thought that these languages - known as Proto-Sinaitic and Proto-Canaanite - had been developed from Egyptian hieroglyphs.

But this new evidence has prompted the theory that the development took place in Egypt itself, during the period of the Middle Kingdom.

Dr Darnell believes that scribes among foreign mercenaries serving with the Egyptian army developed the simplified writing - initially through the work of hieroglyphic scribes who simplified the pictograms into a rudimentary alphabet for use by Semitic speakers.

This is well before the probable time of the Biblical story of Joseph being delivered into slavery in Egypt, so predating the traditional seeds of a Semitic presence in Egypt.

Greek origins

So far, scholars who have studied the inscriptions have not managed to translate them, but they have succeeded in deciphering some letters.

M is formed of a undulating line deriving from the hieroglyph for water, very similar to the later Semitic letter for M.

Sumerian cuneiform was long thought to be the oldest writing, but its claim is now disputed

A and B were later developed by the Phoenicians and latter-day Canaanites before being passed to the Greeks between 1200 and 900 BC.

From the Greek words for A and B - alpha and beta - we derive the word alphabet.

The earliest primitive writing, the cuneiform developed by Sumerians in the Tigris and Euphrates Valley of present-day Iraq, remained entirely pictographic until about 1400 BC.

The Sumerians have generally been credited with the first invention of writing, around 3200 BC.

But fragments of pottery dating back 5500 years, found at Harappa in Pakistan, may have trumped the Sumerians' claim.