The beginning of the sentence prompts a hypothetical "Why?" that should be answered. "Because" is the most straight forward way to answer a "Why" question. It doesn't quite "flow" in the sentence, and I think ease of reading is an important consideration.

"Since" is not quite as straight an answer, but it flows a bit better.

"Due to" is the least straight forward, but definitely flows the best. <Thanh> suggestion of "after being arrested" is most like this alternative-not quite as grammmatically precise, but more pleasing to the ear.

I currently prefer the "due to" formulation by a hair over "because of". So right now, I like:

No need for "very"

<but within a year Loewenthal could play level>

A bit too colloquial for my tastes. Something simpler, like "within a year, Loewenthal could compete at even odds"

<After some weeks, however, he chanced upon a chess puzzle in a newspaper and contacted the editor of the New York Albion, who in turn gave him a letter of introduction to Charles Henry Stanley. >

What does this mean? Was the puzzle in the New York Albion? If so, I'd prefer "After some weeks, (however is a wasted word) he chanced upon a chess puzzle in the New York Albion and contacted the editor, who in turn gave him a letter of introduction to Charles Henry Stanley." Beyond that, there's a bit of a mystery here as to why Loewenthal contacted the editor, to seek a job as a columnist, to find an American with an interest in chess, to find someone to initiate him into the American chess scene, etc. The next sentence (Stanley knew Loewenthal was a Hungarian chess master and ushered him into the fold of the New York chess circle) suggests the last alternative, but it probably should be clarified. And if Stanley had a relationship with the Albion, that probably should be clarified.

<Staunton's Protege>

Not a big deal, but the most common form is protege'. Protege is fine though.

<There were other reasons to remain in England, however, notably the chance to test himself against the best masters in the world.>

I don't like the "however" there. Maybe " ........in England, most notably......"

grueling

<Staunton was disappointed by the result, but contrary to a widely held and persistent belief, he did not break off cordial relations with Loewenthal at this time, although he did indeed do so in 1857.>

Staunton was disappointed by the result, but contrary to a widely held and persistent belief, he did not break off cordial relations with Loewenthal at this time.

(The subsequent sentence starting "The actual falling out between Staunton and Loewenthal likely arose...) makes the "although he did indeed do so in 1857" redundant).

<Not only that, he withdrew his longstanding public support>

He also withdrew his longstanding public support.....

<This prompted an anonymous letter to the Illustrated London News mocking Loewenthal for such a minor accomplishment- as if beating Anderssen, even in a single game, could ever be considered a minor feat.>

I'm going to think on this one. For starters, I'm not sure an anonymous crank's comment is worth a sentence in this or any player's bio.

<In 1858 Loewenthal became the first European master to face Paul Morphy, now a grown man at the height of his powers out to prove he was the greatest chess player in the world.>

Maybe .....Morphy-now a grown man determined to prove he was the greatest chess player in the world.

<The controversy arose largely from one exceedingly strange proposal, that a player was not obligated to change a promoted pawn into a different piece. This engendered a heated argument over English chess rules that was not finally resolved until the early 20th century.>

Outstanding as usual, and thanks so much for the benefit of your work.

I agree with all your edits and I'm in process of putting them in now. With regard to the "Albion" mystery, there was context missing that I've tried to put in to make it more clear. The source only implies the Albion had a reltationship with Stanley, but it's a clear implication.

You can read the original article from <Loewenthal> here. The pertinent passage is at the start, on pages 389-91 of this book which you can read for free on Google- http://books.google.ca/books/about/....

There was a keen sense of competition at this time between foreign and English-born masters that sometimes engendered prejudice against the foreign players. The main event at Manchester 1857 was the consultation game which pitted a team of "English masters" against "foreign masters"-Anderssen / Horwitz / Kling vs Staunton / Boden / Kipping, 1857. In the final round of the tournament "English" Boden faced "foreign" Lowenthal and really, the affair was not settled- the final score was drawn. Most chess fans would have been rooting for Boden.

The letter complaining about Loewenthal's victory does sound like a crank wrote it, but the fact is that it wouldn't necessarily have been received as such by contemporary readers, many of whom would likely have agreed with the sentiment, partly out of a prejudice against foreign masters.

This direct link to Loewenthal's article may save some time:

http://books.google.com/books?id=U9...

The chess column from the <New York Albion> for 1850 is available at Nick Pope's <Chess Archaeology> site: http://www.chessarch.com/excavation.... This particular column, from February 9, 1850, may be of interest:

http://www.chessarch.com/excavation...

Maybe "Most of his colleagues in the Soviet bloc, with the notable exceptions of Alexander Koblents and Paul Keres, avoided publishing his games, or even mentioning his name in public."

1. Most of his colleagues in the Soviet bloc, with the notable exceptions of Alexander Koblents and Paul Keres, avoided publishing his games, or even mentioning his name in public.

2. Most of his colleagues in the Soviet bloc(with the notable exceptions of Alexander Koblents and Paul Keres)avoided publishing his games, or even mentioning his name in public.

I switched to <The Dawg> but then after I worried you might not like it.

Actually last night I was thinking of a list of potential nicknames offered up for your approval. <Howard> was amenable to this in the past, and believe it or not he actually okayed "Howard the Wonder Hedgehog," although I settled on <H>, which he was already using, despite <Big's> controversial claim to have coined that one.