There is an old story of how the Moorish kings' servants created rice dishes by mixing the left-overs from royal banquets in large pots to take home. It is said by some that that word paella originates from the Arab word “baqiyah” meaning left-overs.The term Paella actually refers to the pan that it is cooked in. All the way back to the ancient Sanskrit language the term Pa means …to drink, and the Roman culture from the latin made words like Patera, Patina , Patella which could mean a container to drink, or perform other culinary functions.
It would seem a natural dish, since rice is grown in Spain, and all meats, and seafood in some regions are plentiful, that this dish would be a natural. Since there are many workers in the fields, cooking it over an open fire also would be the most practical. Spain is not known for forests and lots of timber, so the small available twigs and branches from pruning that are green gave a quick hot fire instead of a slow burning one from logs.
So the size of the pan grew instead of the depth, so you could get a hot fire a maximum evaporation.
Most experts agree that the dish was developed in the Spanish city of Valencia.
Valencia is where the Romans introduced irrigation and then the Arab conquerors that brought rice, prefected it. Many folks say the best Paella and most authentic still comes from Valencia.
Also in Islamic Andalusia Spain symbolic dishes with rice and different meats and vegetables like a casserole were cooked for special occasions. Some of these dishes may be the roots of some of the Paella recipes.