Based on traditional accounts, Tthe Celtic population remained in Ireland, Wales, and Scotland; however, they were wiped out in England by the Angles-Saxons.

changed uppercase "The Celtic" to "the Celtic"

However, some new genetic studies of modern Britons showed that the Angeles-Saxons barely made a splash in the English genetic pool and even the Vikings had a larger genetic presence than them.

"gene pool" instead of "genetic pool"
correction to spelling of "larger" (was "lager")

Many people think thatconsider the Celts werto be Britain's earliest indigenous inhabitants who, as they had migrated from central Europe to present-day England and the rest of the British Isles during the Iron Age.

It's hard to paraphrase the information you must have read into something more basic. What you've written implies that many people thought that the Celts were Britain's indigenous inhabitants, but actually they were not and it was someone else.

Brief ofSummary of an Article

I am posting a briefsummary of thean article that I read today within my own words.

A brief is a detailed summary and is usually used as legal terminology.

However, a brief summary means a very short summary.

Some 1,000 years later, the Celts were overrun by Germanic tribes, from whom the modern population of England is said to be descended.

Based on traditional accounts, Tthe Celtic population remained in Ireland, Wales, and Scotland; however, they were wiped out in England by the Angleso-Saxons.

This story has informed the identity of modern Britons, with the Scottish, Welsh, and Irish identifying themselves as differently from the English in terms of ethnicality and cultural aspectse.

However, some new genetic studies of modern Britons have showed that the Angeleso-Saxons barely made a splash in the English genetic pool, and that even the Vikings had a lager genetic presence than them.

The invasion by the Angles-Saxons seems to have occurred at only a limited level.

Your sentenced is fine, but this adds emphasis.

They replaced the rulers at that time; however, they left resident populations intact.

Thank you for your patience inwhile reading this.

BA brief of Aarticle

I am posting a brief of the article that I read wrote today within my own words.

Many people think that the Celts were Britain's indigenous inhabitants who had migrated from central Europe to the present-day England and the rest of the British Isles during the Iron Age.

If you start with "many people think that..." you should say if this is true or not true by adding something in the range of "..whereas they actually.." or something like that.

Some 1000 years later, the Celts were overrun by Germanic tribes, from whom the modern population of England is said to bhave descended.

Based on traditional accounts, Tthe Celtic population remained in Ireland, Wales, and Scotland; however, in England they were wiped out in England by the Angles-Saxons.

This story has informed you of the identity of modern Britons, with the Scottish, Welsh, and Irish identifying themselves as differently from the English in terms of ethical and cultural aspects.

Brief of ArticleArticle summary

I am posting a briefsummary of the article that I read today with my own words.

Based on traditional accounts, The Celtic population remained in Ireland, Wales, and Scotland; however, they were wiped out in England by the Angleso-Saxons.

This story has informed the identity of modern Britons, with the Scottish, Welsh, and Irish identifying themselves differently from the English in terms of ethnicality and cultural aspectse.

However, some new genetic studies of modern Britons showed that the Angeleslo-Saxons barely made a splash in the English genetic pool and, with even the Vikings hadving a larger genetic presence than themin the pool than the Anglo-Saxons.

The invasion byof the Angleso-Saxons seems to have occurred at a limited level.

They replaced rulers at that time; however,, but they left resident populations intact.

Thank you for your patience inwhile reading this.