Ann Semark was the daughter of; Thomas Semarc, daughter of Alice Lexham [father William Lexham of Norfolk].
Sir William Lexham daughter Agnes married Sir John Cheyne. [not Sir Thomas Laxham as stated by Adeline Bedford see below]
Sir John Cheyne devised the manor of Chenies to his wife Agnes, daughter of Sir William Lexham, who being childless, left it by her will, dated 1494, to Sir David Phelyp and his wife, her niece Anne Semark and their heirs, remainder in tail to Guy Sapcote, the son of her niece by her first marriage. Sir David and his wife dying without issue the manor came to Anne, daughter of Sir Guy Sapcote.
Anne Semark was a Kinswomen to the wife of David Cecil.
Extract from Chenies Church and Monuments by Adeline Marie Bedford published 1901
The first appearance of the name Cheney or Cheyne in the pages of history dates from the year 1364, when Edward III granted the Manor of Drayton Beauchamp to one Thomas Cheyne, his shield-bearer, a gentleman of some repute in the county of Buckingham, inasmuch as he was the owner of the manor of Cheynes (or Isenhampsted-Cheynes), which had come into the possession of his family a century earlier. This manor had been originally a royal hunting-box, Edward I and Edward II having occasionally resided there. Sir John Cheyne, who next emerges into view, bequeathed the manor before his death, which took place in August, 1468, to his wife Agnes, the daughter and co-heiress of Sir Thomas Laxham. This Lady Cheyne, who was childless, married a second time one Edward Molineux , who died in 1484, the brass which commemorates her and second husband must have been removed to its present place near the porch, from the floor of the Church, as the inscriptions are much worn. This Agnes, Lady Cheyne, left the estate by her will, dated 1494, to her niece Anne Semark, wife of Sir David Phelip.
An interesting brass, bearing an inscription from the book of Job, commemorates this lady. Anne was the heiress of the Semarks, and the possessor of Thornhaugh, Eaton Socon [See Below], and other goodly manors, but Sir William Sapcote (her first husband) , whose family would seem to have been partisans of the White Rose, suffered sequestration of his own and his wife’s estates, and the attainder was only reversed on the petition of his son, Sir Guy Sapcote.
It was probably in this period of straitened for fortunes that Agnes, Lady Cheyne, selected Anne, Lady Phelip, and her son, Sir Guy Sapcote, as her heirs, in tail, the remainder in fee being awarded to John Cheyne of Bois. This selection caused some irritation in the Cheyne family, and , as Dame Agnes had made two wills in her lifetime, litigation ensured. The arbitrators decided in favour of Lady Phelip and her son, thus awarding Chenies to the Sapcotes and their heirs, John Cheyne receiving some other lands under dispute. An abstract of the will of Dame Agnes is given in Coles’ MSS., vol xxxix., pp.38-49. This work contains a great many notes collected by Browne Willis relating to the Cheyne family, one of which is an echo of the asperity with which the disposal of the property of the heiress of the Semarks was regarded. “Dame Agnes Cheyne” he says was the daughter of Sir Nicholas Cogenho (which statement is incorrect, though she owned a manor of that name). “She gave away Chenies from the family.” In process of time the estate (with the redeemed manors) passed to the only daughter of Sir Guy Sapcote, Anne, who married Sir John Broughton of Toddington, in Bedfordshire, and by him had one son and two daughters, The son died young, and the daughters were under the wardship of Cardinal Wolsey in virtue of one of his high offices. Sir Thomas Cheyne (the then representative of the Cheyne family) married the elder daughter, doubtless to strengthen his claim on the estate, and involved himself in a fierce dispute with both King and Cardinal, regarding the wardship of the younger. Anne Boleyn supported him, and feeling ran high on the subject.
This Sir Thomas was a remarkable character, even in his vigour and originality, and his eulogy by Holinshed is worth quoting : “ He kept so bountiful a house and was so liberall and good to his men that well was that nobleman’s son, or gentleman’s son or other that might happen to be preferred into his service.”
The picture of this prosperous household, in which “great wages were trulie paid every quarter and bord wages every Sundaie,” contrasts with the ill-regulated house at Toddington, of which Sir John Russell complains when writing from Ampthill to Cardinal Wolsey in 1529. The youth of his “son Broughton,” as the step-father affectionately calls him, accounted for some disorder; but the ferment created by the alliance with the Cheyne family was a more serious matter. Sir Thomas was, however, a great gentleman. “ The Frenchman,” continues the chronicler, “ both feared and loved him wonderfullie.” He served three Kings and two Queens, as pleased them all. “In the end he was so worthie a gentleman, as his want cannot be lamented by all good and true English hearts. But the Almightie must be served when His good will and pleasure is.” Such was Sir Thomas Cheyne.
The family retained the estates of Chesham Bois, and in1680 a peerage was conferred upon its representative with the title of Viscount Newhaven, which peerage became extinct in 1728.
But to return to the descendant of the Sapcotes, Anne, Lady Broughton. On the death of her first husband she married Sir Richard Jerningham, a well-known personage at the court of Henry VIII. Sir Richard, with his wife, was present at the Field of the Cloth of Gold.
In 1524 (six years after her second marriage) she again became a widow, and shortly after bestowed her hand on Sir John Russell, afterwards created first Earl of Bedford in 1550.
On the death of her son by her first marriage, the question of the succession to the Chenies estates was again raised, but a final settlement was made in 1560, with consent of John Cheyne, the descendant of the ancient proprietors, in favour of Francis, her only son by her third marriage, who succeeded his father as second Earl of Bedford in 1556. The chronicler Leland visited the manor house during the life-time of the first Earl and Countess of Bedford, and thus describes his impressions:
“ The old house of the Cheynies is so translated by my Lord Russel that hath that house in the Righte of his Wife that little or nothing of it yet in a manner remaineth ontranslatid : and a great deal of the House is even newley set up made of Brick and Timber : and fair loggings be new erected in the Garden. The House is within diverse Places richly painted with antique workes of White and Black. And there be about the House two Parkes as I remember. The Manor Place standeth at the West Ende of the Parishe Churche. In the Parishe Churche on the North side of it as in a Chapelle, be two Tumbes of the Cheynies Lords of the Manor and the small village being their name.” (Leland’s Itinerary, fol 122)
The tombs mentioned are in the Bedford Chapel, and Sir George Scharf was of opinion that the mutilated figure of the Knight represents one Sir John Cheyne, who died between 1395 and 1401.
“ The costume of the Lady,” he adds, “ is that of the fifteenth century and closely resembles that in the effigy of Joan of Navarre, second wife of Henry IV at Canterbury.”
The ancient estate of Cogenho was sold by the Cheynes to buy Chelsea from the Duke of Hamilton – hence Cheyne Walk, Chelsea.
Anne, Countess of Bedford, bequeathed the sum of £50, by her will, dated 1557, to Henry, son of her daughter, Lady Cheyne.
Cogenho Note: Northamptonshire
1584 Nov. 9.Francis Cheyne.Second son of John C. of Cogenho, and Chesham Bois, Bucks, whom he succ. in the estates on his death 1585, (his elder bro. John being disinherited,) ent. the Inner Temple Nov. 1568, was knighted July 1603, M.P. Cardigan 1584-5, 1586-7 and d.s.p. 1619. His great nephew was cr. Viscount Newhaven 1681, which title became extinct 1738. Francis Cheyne's sister m. Sir John Perrott (Pembrokeshire).
In the 5th year of Edw 1V Richard Barry clerk made a conveyance of the Manor and advowson of Cogenho to Sir John Cheyne and Agnes his wife, daughter of William Lexham.
The interesting footnote/pedigree : This William Lexham must be the same person with William de Cogenho who in the Fine Roll, anno 12 Ric II is expressly named the father of the said Agnes.
Bridges then draws the Cheyne pedigree with Agnes d of William de Cogenho, Agnes ob as we know 1494. Bridges also states that Agnes and John had one child, Alex ob 1445.
The Cogenho estate was sold to purchase Duke Hamilton's estate in Chelsea  ,Cheyne Walk
Eaton Socon Note from further research: From A History of Bedfordshire [Victorian] – No mention of Ann Semark but would seem to be the correct Cheney/Cheyne family.
In 1399 Katherine daughter of Laurence de Pabenham received pardon, on payment of a fine of 10 Marks, for acquiring two-thirds of Eaton Manor from her father without licence. This was probably on the occasion of her marriage with Sir William Cheney, on whose death she married Sir Thomas Aylesbury , who died in 1418. Eaton Manor next passed to Laurence Cheney, who held one fee of Eaton Barony in 1428. His son Sir John Cheney died seised in 1489. In 1492 Thomas son of John Cheney, and the last of the name to hold the manor, was engaged in litigation with John Ormond and Joan his wife, who declared that Thoms d’Engayne (ob 1367) did not die witout issue, and that they represented such issue. Their claim came to nothing as regards Eaton, which Elizabeth sole daughter and heir of Thomas Cheney, bought in marriage to Thomas Lord Vaux of Harrowden…… In 1708 the Duke of Bedford purchased the Manor.