A letter written by Charlotte Bronte as she grieved over the death of her brother Branwell and fretted about the health of her younger sister Emily is on its way back to Haworth.

The Bronte Parsonage Museum outbid other collectors to get the letter for $55,000 (£39,000) at an auction in New York.

It will join a treasure trove of artifacts acquired by the museum in Haworth over the past six months.

This latest item was written by the author of Jane Eyre, on October 18, 1848, shortly after Branwell died. It was sent to William Smith William, the reader at her publisher Smith Elder and Co.

Ann Dinsdale, the museum’s collections manager, said: “This was a very sad period of her life. Branwell had just died and Emily was showing symptoms of the TB which would kill her three months later.

“The letter doesn’t refer to these things, but it talks about her being ill. I think her deep unhappiness was manifested in this ill health.”

Mr William became a friend to Charlotte having spotted her potential as a writer when she sent her first novel The Professor to the publishing house. It was not accepted but he encouraged her to write Jane Eyre, which the company published.

Mrs Dinsdale said staff followed the auction online and were very excited when they realised the hammer had gone down on their bid.

Once the letter arrives back in Haworth, it will join the other recently bought artifacts including a poetry manuscript written by Charlotte as a 13-year-old and Emily’s artist’s box.

The Bronte Society paid £32,000 for the box and geometry set at auction in London in December and $50,000 for the miniature manuscripts.

They are now on display.