origins of the assegai?

[pallas]

i know this was the main weapon of the almogavars (who seem to have enjoyed a more dubious reputation for ruthlessness than the other crusading and knightly orders that were their contemporaries) but the name "assegai" seems to be applied to long lances/spears throughout the iberian peninsula and north and east africa. i know assegai is a portugese term, but i somehow doubt that these weapons originated in portugal.