Kingdom of Doggerland

Correct my grammar, please. I’m not fluent in English.

Doggerland (pronounced /dɔːgɛrlənd/) officially the Kingdom of Doggerland is a nation in the North Sea, that is, north of the Viking-Bergen Archipelago that leads into the North Sea.

Etymology
The name ”Doggerland” comes from the former landmass of Doggerland (in Earth’s timeline) which comes from the Dogger Bank, a former sandbank in the North Sea (once again, in Earth’s timeline).

Ice Age
In this timeline, the coasts are more mountainous and Doggerland is higher-ground. Originally, the Maglemosian culture settled here because they wanted to hunt for some food.

Stone Age
As the glaciers melted, Doggerland become warmer. People began to settle in the north of the country. The people also spoke a similar language to what is now spoken in Getnode.

Bronze Age
As the Stone age ended, people started using bronze for their weapons. With the arrival of the Celts in the south, the northern Maglemosian people started moving upwards to north of the Novons River, (northernmost river in Doggerland). Others moved to mainland Europe where they currently reside in Getnode. They also invented their own writing system.

Iron Age
As the Celts inhabited most of the land, they divided themselves into many tribes. As the Romans invaded, they formed their own alphabet.

Romans
During the Roman times the entire south of the nation was highly Romanized, although the north was free, from the Romans due to just cold weather and the sleek bareness of the land, plus the Celts there were ruthless

it was also a part of the Gallic empire when it broke away,

The Romans were also scared by the Invalids, who rode mammoths into battle and would crush Roman soldiers.

Middle Ages
After the Romans left it was similar to England, except this time they walked and captured the entire south and a lot of the north of doggerland, the peninsula still belonging 98% to the Celts and The Invalids In the north.

they created Two Kingdoms, Witfyrth and Cereseaxe, They Eventually United Into Sebrigland,

In the North King Padrigos Of The Clan Mabdudeganfider refused to pay the Vikings a fee of 200 gold for protection so this started the 200 year war, The Clans Quickly Fell to the norselaw, then they marched into Sebrigland but 60 years later the Norselaw was officially conquered by Sebrigland officially Uniting the kingdom of Doggerland

There Were little wars between its neighbours during the time until the 1400's when they invade The Netherlands and succeeded only to go on to Germany, eventually creating the Maglian Empire which lasted for 232 years. Eventually, Reginald III lost His territory and was pushed back to The Netherlands.

Colonial
Doggerland was rather successful in colonialism, colonizing the island of Bermuda, Cuba, Haiti, Florida, Dominican Republic and Bahamas, and the Yucatan peninsula along with Central America and large chunks of Canada.

Victorian
Eventually they lost Haiti and Cuba in the Muicyred War of independence. Reginald IV ruled From The mid-1800's to the 1930's - then his son Reginald V took control and is currently king.

They also lost The Netherlands in an independence referendum.

Modern
In modern times, Doggerland is a successful nation. In WW1 it was an allied power and the same in WW2. Their terrain proved hard for the Germans to blitzkrieg. They joined the EU in 1976 and changed their currency to the Euro in 2007.