At twelve or thirteen she became a maid-of-honour to Mary of Modena, the new Duchess of York. She was not as beautiful as her elder sister Frances who was being pursued by the Duke of York. At the Court she was befriended by the Duke's daughters Mary (eleven) and Anne (eight) as well as the fifteen-year-old Mary of Modena. The friendship with the future Queen Anne would last for more than twenty-five years. 
At fifteen she found herself to be the object of John Churchill's desires. John Churchill's sister Arabella had been the mistress of the Duke of York who had fathered four children by Arabella. Sarah would 
always be disparaging about Arabella "and ther train of Bastards". She acted cool, almost cruelly, and it would take three years before she consented to become his wife in secret. Theirs would remain a 
special love-match which would last all their lives, even though she never was submissive nor obedient. She was proud, imperious and, in later life, quarrelsome. 
It would take another five years before they had their own home. In the meantime they resided with Sir Winston, her father-in-law or at the Court. After the Popish plot of 1678, the Duke of York went first 
to Brussels and later to Edinburgh with both John and Sarah Churchill in attendance. When Charles II allowed his brother and his entourage to return to England, John and Sarah Churchill built a house at 
Holywell in Hertfordshire. Their first child, Harriet, died as a baby. Henrietta, born in 1681, survived to be followed by Anne, Elizabeth, Mary, John and Charles. However, Charles died in infancy and John, as Marquess of Blandford, died aged thirteen in 1703. 
In 1683 Princess Anne married Prince George of Denmark and Sarah was appointed Anne's Lady of the Bedchamber. Anne loved her boring husband but still retained a strong emotional tie with Sarah. They 
would address each other in correspondence as Mrs. Morley and Mrs. Freeman. Their husbands were called Mr. Morley and Mr. Freeman and Sydney Godolphin was referred to as Mr. Montgomery. 
When the Duke of York, Anne's father, became King as James II, he made the Churchills Lord and Lady Churchill of Sandridge. But peace was shattered when the Duke of Monmouth landed at Lyme in Dorset in 1685 with the intention of removing the Catholic James II and becoming king himself. However, mainly due to John Churchill, Monmouth was defeated. 
In 1688, when Prince William III of Orange had taken up the invitation to invade England to replace James II, Lady Churchill fled London with Princess Anne and defected to the invader. At the 
coronation of William III and Mary II, John Churchill became Earl of Marlborough, and was soon sent to war on the continent. However, the new King and Queen disliked and distrusted the Earl of Marlborough and disapproved of Sarah as she was also close and influential on Anne, Queen Mary II's sister. Sarah was the cause of disharmony between the two sisters which resulted in an irreparable rift. This resulted in the dismissal of John Churchill in all his capacities and, after a short spell in the Tower, he was left unemployed for a considerable period. 
The death of William III made their friend Queen of England and Queen Anne made John Churchill Captain-General of the army and Sarah Groom of the Stole, Mistress of the Robes and Comptroller of the Privy Purse. Their daughters, Henrietta and Anne, became Ladies of the Bedchamber. However, Sarah's support for the Whigs, detested by Queen Anne, started to spoil their friendship and after a while Queen Anne's patience ran out. 
A cousin of Sarah, Abigail Marsham, replaced Sarah in Queen Anne's confidence and after a while all friends of John and Sarah Churchill were removed from office. Sarah became more tactless even to Queen Anne and behaved with indelicacy at the death of Queen Anne's husband, Prince George of Denmark. From now on Sarah stayed away from Court and this was the end of twenty-seven years of friendship. In 1712 the Marlboroughs toured the continent to return to England a day after Queen Anne's death. 
The new King, George I, restored the Duke of Marlborough to his previous positions, and so for 
several more years he was again involved with affairs of state. However, in 1716, the death of their 
daughter Anne caused Marlborough to have a paralytic stroke, but he still lived for another six years. These last years of his life were somewhat overshadowed by Sarah's quarrelsome nature. Even at his 
deathbed Sarah was not on speaking terms with their two remaining daughters. After his death she made the observation: "He was naturally genteel without the least affectation, and handsome as an angel tho' ever so carelessly dressed". 
As his widow she lived another twenty years---spent arguing, correcting, justifying as well as litigating. Her main concerns were her houses, estates and her grandchildren. The behaviour of the latter she recorded in a book entitled "An Account of the Cruell Usage of my Children". However old Sarah may have been, she was rich and renowned and still received two proposals of marriage. Earl Coningsby asked her too soon after John Churchill's death and the arrogant Duke of Somerset she put in his place with her reply: "If I were young and handsome as I was, instead of old and faded as I am, and you could lay the empire of the world at my feet, you should never share the heart and hand that once belonged to John, Duke of Marlborough." 
Even though she cared little for the Hanoverians, she tried to have her favourite granddaughter, Lady Diana Spencer, marry the Prince of Wales. After this was prevented by Walpole, Lady Diana married a 
future Duke of Bedford and died of tuberculosis at the age of twenty-six. One grandson she disliked was William Godolphin, Marquess of Blandford and heir to the Marlborough title. Even his own kind 
sister Henrietta called him "Lord Worthless". At first Sarah was shocked when he married the daughter of a Dutch burgomaster but the girl turned out to be rich and sensible. However, "Willigo" died two 
years later of drink and, as he was still childless, the new heir to the Marlborough title was a son of Anne Churchill, Sarah's third daughter. 
But Charles Spencer wasn't liked by her either. She regarded him extravagant and suspected him of gambling. As well, she at first didn't like his choice of wife either as her father had been a political opponent of her late husband. She may have disliked Charles, but she positively hated his sister Anne yet loved the younger son, the Hon. John Spencer. 
At a family gathering she commented: "What a glorious sight it is to see such a number of branches flourishing from the same root!" After which her favourite grandson, John Spencer, muttered: "Alas 
the branches would flourish far better if the root were underground!" As Blenheim and the Ducal title was to go to Charles Spencer, in her will she left Althorp and a large fortune to the Hon. John Spencer. 
 

Source: Leo van de Pas