Name: Born Anne Norton; married Anne Turner
Parents: Thomas Norton of Hinxton, Cambridgeshire; Margaret Norton
Husbands: Dr. George Turner
Children: 3 unnamed (by her lover Sir Arthur Mainwaring)
Unsure if she had any by Dr. Turner?
While biographical data for Anne Turner isn’t as readily available as for persons of nobler birth, it seems beyond reasonable doubt that she was born to a Thomas Norton of Hinxton, Cambridgeshire and his wife, Margaret, daughter and sole heir of a Somerset knight. There is no date for her birth, but there is record of the couple’s daughter Anne being baptized on 15th Jan 1576. Anne herself gave her birthday (indirectly) as the 5th of January, 1576, claiming that 5th Jan, 1616 was the date she would have turned 40. 
The family seems to have held some status – as mentioned her mother is given as daughter and heir of a knight and the family is claimed to have had a shield. One of her brothers is said to be a servant to Prince Charles at the time of her death  and one sister is named as Mrs Wedge in Aldersgate Street.
Herself, she married a “doctor of Phissick”  of some renown who at the end of his life was Treasurer of the College of Physicians. Dr. Turner was a Catholic, and it seems that Anne was too, although lapsed. 
Anne is described as having been pretty; a contemporary verse from the time of her trial dwells on her ivory brow and delicate limbs and “locks like golden thread” . This may well just have been poetic license, but there is absolutely nothing to contradict it.
Dr Turner was considerably older than his wife, and besides being a successful doctor, favoured by Queen Elizabeth , he was also connected to the darker side of Elizabethan science. He had some interest in alchemy, and some connection with the infamous Dr. Simon Forman, who apparently borrowed and copied alchemical writings of Turner’s in the 1590s.  It is likely that it was through her husband that Anne made Dr. Forman’s acquaintance, a connection that would have immense impact on her future destiny.
The relationship between Anne and her husband is a little intriguing, since it seems that for a large part of the marriage, she was amorously involved with Sir Arthur Mainwaring, with her husband’s tacit or express approval. She is said to have had 3 children by Mainwaring and there seems to have been no doubt that they were not her husband’s and it seems that this was common knowledge. 
Exactly how she knew Frances Howard isn’t clear. She herself said at her trial in 1615 that “she was ever brought up with the Countess”, and they seem to have been close and very affectionate; Frances addressed her in writing as “Sweet Turner” and signed herself “Your sister, Frances Essex”  and Mrs Turner’s last act before being hanged was begging permission to pray for Frances, whom she’d earlier called “as dear unto me as my own soul”. 
Frances, who was the daughter of the Earl of Suffolk, the Lord Chancellor, was from 1604 married to the Earl of Essex, in a state of increasing misery. The couple did not get on and Lord Essex turned out to be unable to consummate the marriage despite repeated attempts. Husband and wife spent as much time away from each other as possible, and Frances, who was renowned as one of the greatbeauties of the Jacobean court, caught the eye of the man of the moment, the royal favourite Robert Carr (later Lord Rochester, later Lord Somerset). What might have started out as a flirt soon turned into something more serious and evidence suggests that Anne was aiding and abetting Frances in her amorous pursuits. 
It seems that after Dr Turner died in 1610, Anne ended up in some financial difficulties, but she eventually found a living making yellow starch which was a French fashion that was extremely trendy in the 1610s (and considered an especial affront to God for some reason). On her Wikipedia page, it is claimed that she ran houses of ill-repute in Paternoster Row and Hammersmith, but I haven’t been able to verify that beyond an unsubstantiated claim on the internet (the only reference to a house in Hammersmith I have encountered is one that was claimed that Frances used for a clandestine meeting with her lover, but there is absolutely nothing that implies that it was Anne’s; I’d even say that the wording by the witness pretty much contradicts such an interpretation). Anne herself claimed that “she had no means to maintain herself and her children but what came of the Countess.” 
Mainwaring was apparently still in her life, but didn’t intend to make an honourable woman out of her. In a rather unusual gesture, Dr Turner had left his wife’s lover £10 in his will so that Mainwaring would finally get a ring on her finger, specifying it should be inscribed with Fato jungunt amantes (Lovers joined through fate) but he seems not to have taken the bait.  Desperate to make him agree to marrying her, she engaged Dr. Forman to supply her with some supernatural help. Before long, Dr Forman was also assisting Frances in securing the heart of Lord Rochester. 
Exactly what this help consisted of isn’t clear, but Dr. Forman was a practitioner of the occult, who spent a great deal of his time supplying the needy with various aids for their love lives. At Anne’s trial in 1615, several objects of dubious nature were produced, and it is reasonable to assume they came from Forman. These include two “pictures of black lead, a man and woman naked, belly to belly in bestial fashion” and a parchment with a piece of human skin attached to it. On this was written the names of the devils “who were conjured to torment the Lord Somerset and Sir Arthur Mainwaring” if they were faithless.  Apparently Forman wasn’t entirely successful. Somerset did eventually marry Frances as soon as her divorce from Lord Essex had come through, and Mainwaring was on one occasion so tormented by a right frenzy of lust “that through a storm of rain and thunder he rode fifteen miles one dark night to her [Anne’s] house”,  but he persisted in a state of committment-phobia.
Meanwhile, the affair between Frances and Somerset had grown serious enough for her family to initiate divorce proceedings so that they could marry. The grounds were impotenc eon the side of the bridegroom, but only in relation to his wife, the suggestion being that it was caused by witchcraft (since that was a legal loophole). Anne remained by Frances side through the nerve racking turns of her divorce proceedings, and according to certain later claims, she helped her meet Somerset in secret (something that would have made the divorce impossible if known). 
Besides the legal proceedings, a big cloud on the sky of Frances’s potential happiness was the fact that her beloved’s best friend was doing his best to sabotage her divorce and her relationship with Somerset. Thomas Overbury and Robert Carr had long been inseparable, and though Overbury was now imprisoned in the Tower on the grounds of having turned down an offer for a diplomatic mission, he still perceived himself as close to Somerset as ever. In reality, he had been manouvered into the Towern by Frances’s family, possibly with Somerset’s approval, but for some reason he was still perceived by her as a major obstacle to her future happiness. Using Anne as go-between, she became involved in a conspiracy to murder Overbury. 
Exactly how this was done, and if it was done, is unclear due to the poor quality of 17th century criminal investigations, but it seems beyond any reasonable doubt that Frances tried to poison him on at least one occasion. According to her own admission, Anne knew, helped and kept quiet. And it is beyond any doubt that Overbury died in the Tower in September 1613, after which Frances’s divorce came through. She and Somerset married in December that year.
After the wedding, Frances invited Anne to come live with her, which she did. She later stressed that she did this “not as her servant”  but presumably as her companion. At first, the Somersets lived in luxury and comfort, basking in the love and favour of King James. But before long, tensions arose between Lord Somerset and the King, and the enemies he had amassed during his remarkable rise to favour plotted his downfall. 
If it was through these or just bad luck isn’t clear, but soon rumours about Overbury’s timely demise started to circulate. Sir Gerwase Helwys who had been the Lieutenant of the Tower during Overbury’s imprisonment confessed to Sir Ralph Winwood, Secretary of State, that he had been aware that Richard Weston, one of the keepers, had been given a potion to use on Overbury, which Helwys had stopped. He also stated that after Overbury’s death, Weston had confessed that an apothecary’s boy had been bribed to give Overbury a poisoned enema. 
From there on, the whole house of cards came down. Weston told on Anne, who was imprisoned, and both Helwys, Weston and Anne were tried for the murder. Anne’s trial took place on the 7th of November 1615, and she was charged with “comforting, aiding and assisting” Weston in poisoning Overbury. Anne denied everything, but she was found guilty and sentenced to death. Chief Justice Coke called her “a whore, a bawd, a sorcerer, a witch, a papist, a felon and a murderer, the daughter of that devil Forman.”  It wasn’t until after the trial, when given spiritual comfort by a minister, that she confessed and implicated Frances. 
She was brought to Tyburn on 14 November 1615, between ten and eleven in the morning, wearing her own yellow ruff. Entreated by the minister to speak to the crowd, she made a very remorseful speech in which she cried out against the corruption of the fashinable world, making special mention of powdered hair and yellow ruffs.  After this she asked if she may pray for Frances, and when answered that this was a charitable deed, she said: “I must pray for her, and whilst pray for her whilst I have breath.”
Then kneeling upon her knees in the cart, a prayer was read unto her by the ordinary, which she repeated after him, and likewise the Lord’s Prayer; which being ended, the rope was put about her neck, being before upon her shoulders, her hands were bound with a black silk ribbon, as she desired, and a black veil, which she wore upon her head, being pulled over her face by the executioner, the cart was driven away, and she was left hanging, in whom there was no motion at all perceived.
Amos, p. 224, quoting in turn State Paper Office; Domestic papers, 1615, Nov. 14, No. 290
 Somerset, Unnatural Murder p. 86, http://nq.oxfordjournals.org/cgi/pdf_extract/199/mar/113-b
There was a persistent rumour that she was really the daughter of the infamous Dr. Simon Forman, but I think that comes from an unfortunate remark by Sir Edward Coke at her trial. However, when he called her “a daughter of the devil Forman”, he most likely meant spiritually in that she was his pupil in the dark arts.
 Amos The great oyer of poisoning : the trial of the Earl of Somerset for the poisoning of Sir Thomas Overbury, in the Tower of London, and various matters connected therewith, from contemporary mss. p. 221
 Somerset, p. 331
 Amos p. 221
 Somerset p. 87, Amos p. 220-1
 Amos p. 49
 Dictionary of National Biography, 1885-1900, Volume 57 Turner, George (d.1610)
 From Turner’s Wikipedia which quotes a book on Forman that I haven’t yet had time to check
 Somerset p. 87-88
 Somerset, p. 87
 Amos p. 222 and 224
 Somerset, chapter 1 and 2
 Somerset p. 88
 Amos p. 221
 Somerset p. 87-102
 Somerset p. 325
 Somerset p. 96
 Somerset chapter 3
 Somerset chapter 3- 6
 Amos p. 222
 Somerset p. 87
 Somerset chapter 5
 Somerset p. 287-291
 Somerset p. 324-327
 Amos p. 219-223Somerset 327-330
 Somerset p. 331