Yes, RIAL is very old patronimical last name. Original of the ancient celtic kingdom of Pontevedra, Galicia, Spain, where there are many "RIAS", like the "Ria of Vigo", or the "Ria of Arosa", which are called "Rias Baixas" or "Rias Bajas" (Low rivers), a special types of rivers that come down from the mountains to the ocean in the green coasts of Galicia. I am from Montevideo, Uruguay and we have a very large family here in South America named "RIAL", which means "many rivers" and all of our ancestors came in the 18th Century from the "Valle Miñor" but from at least three different towns named RIAL with also different heraldic arms. The family of my great grand mother "Rial" was from Bayona in San Pedro de la Ramallosa, and my great grandfather "Rial", was from Rial of Patos, near Panjon where we still have relatives, near the Port of Vigo. So, no doubt, the name Rial is a patronimical! Bye.