Ferelden is somewhere between a historical Rome and England/Scotland to me, though much more of the latter.
All Thedosian countries deliberately take elements from multiple European analogues. Ferelden has stuff in common with both Anglo-Saxon England and Scotland, and even with Merovingian Francia.
As an Asian, I'm pretty much blind to the specifics. I always thought England and Scandinavia have the same things: castles, chainmail warriors, some elite kilt wearing troops exclusive for one part of the place and deadly longbowmen. I'm quite ignorant on the matter. 
That's not really all that wrong, except for the soldiers bit.
See, England, Scotland, Norway, and Denmark all border on the North Sea. For most of human history, trade and travel are easier by water than by land. The North Sea therefore created a sort of unified cultural-economic zone tying all of those regions together: it shows up in archaeology, with many similar artifacts appearing on the various shores of the sea at the same times. The Romans used the North Sea to transport grain from fertile
Britannia to their armies on the Rhine River. Scandinavian traders and warriors plied the North Sea, connecting all of the lands around it, whether by commerce or by mutual fear and loathing of the 'viking' phenomenon. Later, Scandinavians even colonized parts of England, Scotland, and Ireland, and the Scandinavian king Knut the Great held the throne of England in addition to those of Denmark and Norway. The connections even showed up in literature: one of the earliest great works of Old English, the epic poem
Beowulf, is set in Scandinavia, and the
Beowulf audience was clearly assumed to have familiarity with the way Scandinavian politics and war worked.
On the other hand, though, the kilts and longbows and stuff aren't common to all of those countries.

Kilts and other tartan-patterned wool garments are mostly associated with the Scottish Highlands; they're also a fairly modern invention, only about five hundred years old. Longbows have been used worldwide at various times but people generally associate them with Welsh and English military units in the late medieval era, often referring to the 'Welsh longbow' or the 'English longbow'.
Well, Scandinavia used to be a region of three kingdoms that were known collectively as the Scandinavian Peninsula. If I remember correctly, immigration between the three kingdoms and the British Isles (today's UK) was not uncommon and had continued for over a millennium, so there is a number of cultural similarities that remain today as a result.
Yeah, although Denmark's actually not on the Scandinavian Peninsula, while Finland - not a Scandinavian country, but a 'Nordic' one - is.
Usually, 'Scandinavia' refers to the three countries that speak Scandinavian languages: Norway, Denmark, and Sweden. Sweden also used to control Finland, which does not speak a Scandinavian language (although there used to be a
lot of Swedish-speakers there). The two kingdoms of Sweden-Finland and Denmark-Norway were united in the personal Union of Kalmar from 1397 to 1523 until Sweden(-Finland) rebelled, creating its own independent monarchy once again. In 1809, Sweden lost Finland to Russia as part of the Napoleonic Wars, but backed the Allies of the Sixth Coalition and gained Norway from Denmark in 1814. Sweden-Norway lasted until 1905 when Norway was granted its independence. Finland didn't gain independence from Russia until the Revolution, in 1917-1918.
It was also common for Viking raiders to kidnap women and have babies with them. It's apparently how red hair first appeared. One theory has it that women were not always 'kidnapped' so much as 'left with the raiders' because poverty in England at the time was particularly bad.
Feh.
People talk about the viking raiders as being the primary mode of contact between Scandinavian societies and British ones, when that's extremely silly. There were never very many people who would go off to raid; sex undoubtedly happened, both consensual and nonconsensual, but to suggest that any genetic footprint made was the result of such couplings is implausible. There were lots of other reasons for people from Scandinavia to go to Britain: as traders, as hired muscle for local rulers, to escape from political turmoil in their native land, and suchlike things.
And red hair
long predates vikings. Red hair is older than recorded history. The Tocharians of Central Asia and the Tarim Basin were known for their red hair to the Greeks and Romans; Tocharian mummies from a millennium before Alexander have been identified as redheads, including the so-called
Beauty of Xiaohe. Avgvstvs probably had red hair. Polynesian tribespeople have had red hair since before contact with Europeans. Attributing red hair to vikings is folk genetics.