Portugal exists since 1146
From the king of Castille:
King Ferdinand III the Saint to his son, Alfonso X (1252).
Quote from “Estoria de España (1284)”:
“Te dexo de toda la tierra de la mar aca que los moros del rey Rodrigo de Espanna ganado ouieron”
(‘I left you the lands that the moors take from the king Rodrigo of Spain’) (Rodrigo was the visigoth king between 710-711).
Also, from Estoria de Espanna:
“Apartose otro dia con los de Aragón et portogaleses et gallegos et asturianos, essos que y vinieron, et dixoles así el rey don Alfonsso, “Amigos, todos nos somos espannoles et entraronnos los moros la terra por fuerça et conqueriennosla”
(‘He went other day with the ones from Aragon and portuguese and galicians and asturians, those who came, and the king Don Alfonso said to them: “My friends, we all are spanish and the moors entered in our lands by force and conquered them from us”’).
From the king of Aragon:
“Crónica de Bernat Desclot” (1282):
“Yo son hun comte de Spanya a qui dien lo comte de Barcelona”.
(‘I am a count of Spain who is called the count of Barcelona’).
And from the king of Navarre:
Recueil des chartes de l’abbaye de Cluny, volume 4 (1027-1090):
‘Ego Santius, gratia Dei Hispaniarum rex…’
(‘I Santius, by the grace of God, the king of Spain…’)
Umayyad Caliphate could be used in the first ages, and then evolve to the Abbasid Caliphate
(calling the civ just ‘The Caliphate’)
As far as I know, dynasty system is not choosing one kingom or another, is just changing the family of the king.
I supose every civ in the game could potentially have a dynasty system (although I know it’s going to be a chinese exclusive).