Early Egyptians knew how to assemble planks of wood into a ship hull and had mastered advanced forms of shipbuilding as early as 3000BC. The Archaeological Institute of America reports that the oldest planked ships known are the Abydos boats. A group of 14 discovered ships in Abydos were constructed of wooden planks "sewn" together. Discovered by Egyptologist David O'Connor of New York University, woven straps were found to have been used to lash the planks together, and reeds or grass stuffed between the planks helped to seal the seams. Because the ships are all buried together and near a mortuary belonging to Pharaoh Khasekhemwy, originally they were all thought to have belonged to him, but one of the 14 ships dates to 3000BC, and the associated pottery jars buried with the vessels also suggest earlier dating. The ship dating to 3000BC was long and is now thought to perhaps have belonged to an earlier pharaoh, perhaps one as early as Hor-Aha.