I found this: Siddon: This interesting surname with variant spellings Syddon, Sidden, Siddon etc., is of either English habitational or topographical origin. As no evidence can be found of a place called "Siddons" on maps today, it may be assumed that "Siddons" is one of the estimated seven to ten thousand villages and hamlets that have "disappeared", as a result of the dispersal of former inhabitants to make way for sheep pastures at the height of the wool trade in the 14th Century. The placename itself was probably composed of the old English elements "sid", broad, wide and "dun", hill. The name may also be a topographical name, describing "one who lived by a broad hill", from the same old English elements. In 1603 one William Syddon married Faith Burridge at St. James' church, Clerkenwell, London, while in 1621 one William Siddon was christened at St. Olaves, Silver Street, London. Sarah Siddons (1755 - 1831) was one of the foremost Shakespearean actresses of her time and her statue by Chantrey is in Westminster Abbey. Her son Henry (1774 - 1815) received encouragement from Sir Walter Scott and produced creditable plays. The first recorded spelling of the family name is shown to be that of Richard Sidon, (marriage to Jone Aldrige), which was dated April 3rd 1564 at Burnham, Buckinghamshire, during the reign of Queen Elizabeth 1st, known as "Good Queen Bess", 1558 - 1603.

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