Titsey's historical significance stretches back to Roman times, and the historical eastern boundary of the estate follows the London to Lewes Way Roman road. The Romans left their mark at Titsey and there are two Roman sites, including the ruin of a villa (scheduled monument) in Titsey Park.

Titsey was also mentioned in the 1086 Doomsday Book (as Ticesei), however it was in the Tudor period that its significance as a historic estate really began.

The manor of Titsey was acquired in 1534 by John Gresham, one-time Lord Mayor of London and a member of the most prominent merchant dynasty in Tudor England. His elder brother Richard also became Lord Mayor of London. Born at Holt in Norfolk, like Dick Whittington, the Greshams moved to London in their early teens to seek their fortunes. They were very successful. John Gresham became a member of the Mercers' Company, one of the twelve Great Livery Companies, at an early age in 1517. He was prominent in the trade with the Middle East (spices and silks) and the Baltic (timber and skins). He founded the Russia Company, to trade with that far-off and then little-known country, an initiative which was to lead later in the century to the signing of a commercial treaty between Elizabeth I and Ivan the Terrible. He was Sheriff of London and was knighted in 1537 and became Lord Mayor in 1547.

Like all his successful contemporaries he invested his new wealth in land, benefiting from the fluid land-market following the confiscation of church lands, and the dispersal of these and some of the old Crown estates to pay for Henry VIII's extravagant wars in France. Sir John bought the manors of Titsey, Tatsfield, Westerham, Lingfield and Sanderstead on the Kent-Surrey borders as well as other properties in Norfolk and Buckinghamshire leaving his successors a handsome estate the nucleus of which at Titsey has passed down intact to the present day. He was also a public benefactor supporting charities, providing feasts in the City, and founding and endowing Greshams School, at Holt, his birthplace, in Norfolk.

Sir John's nephew, Thomas, took on the Gresham mantle in the City. He joined the Mercers Company, was knighted, and was prominent in overseas trade and banking. His greatest achievement was the Royal Exchange which he built in 1566 as the chief focus for the commerce of the City, on the model of Flemish and Italian examples. He continued his uncle's connection with the Crown and worked as an agent in the Netherlands, gathering information and smuggling gold as well as trading and banking. He became a Chancellor to Elizabeth I, and gained the reputation that with him nothing was impossible. When the Queen came to stay with him at his new house at Osterley in Middlesex she criticised the courtyard for being too small, so in the middle of the night Gresham got some workmen in to knock down various walls and in the morning it was twice its previous size.

Sir John's eldest son William inherited his father's property in and around Titsey and devoted his time to improving the estate and building a new house there. No illustration of the latter exists, as it was largely demolished in the eighteenth century, apart from one small wing at the back which was kept as servants' quarters for the present house at Titsey.

The seventeenth century Greshams sat in Parliament as MPs and supported the King in the Civil War, suffering accordingly. In 1643 the house at Titsey was commandeered by the Parliamentarians but was later returned. At the Restoration in 1660 Charles II created Marmaduke Gresham a baronet as a reward for the family's support of the royalist cause.

The early-eighteenth century saw a dramatic decline in the family fortunes. Sir Marmaduke's grandson, also Marmaduke, was an extravagant spendthrift who let the house fall into ruin and left large debts when he died in 1742. The eldest son, Charles, drowned at sea in 1750 so it was left to his younger brother John to restore the family fortunes after he came of age. He married an heiress, Henrietta Maria, daughter of Sir Kenrick Clayton, and also inherited a second fortune from his mother's brother Edward Hoskins. They both left paintings and furniture which are now at Titsey, and provided him with the money to rescue the estate.

The old house was considered too dilapidated so Sir John demolished the greater part, keeping only a small fragment and built a new smaller red brick house on the old site. Five windows wide with a neat pedimented front door, it was a typical symmetrical Georgian box and remains the nucleus of the present house. Sir John left an only daughter, Katherine Maria, the last of the Greshams. Thanks to her father's prudence she found herself an heiress and in 1804, after the death of both her parents, she married William Leveson Gower, a younger son of Admiral the Hon. John Leveson Gower and first cousin of the Marquess of Stafford, later the 1st Duke of Sutherland.

In the early-nineteenth century the Leveson Gowers were at the heart of the Whig aristocracy and the Duke of Sutherland himself was the richest landowner in Britain; his wife, who was the Countess of Sutherland in her own right, having brought him the whole of the North of Scotland, and his uncle the bachelor Duke of Bridgwater, having left him the fabulous Brdgwater canal fortune. This was the culmination of a process which in five generations raised the Leveson Gowers from Tory Staffordshire baronets to the grandest of Whig grandees and 'Leviathans of Wealth'; each generation marrying an heiress richer than the last, and each generation being raised a step in the peerage: 1st Lord Gower, 1st Earl Gower, 1st Marquess of Stafford, 1st Duke of Sutherland. It was a remarkable record even by the standards of the Georgian aristocracy. In marrying Katherine Maria Gresham, William Leveson Gower was therefore reflecting the tradition of his senior relations.

Sadly, their marriage was short, Katherine Maria died only four years later. They had three children however, and their eldest son, also William, inherited the Titsey estate and an income, it is said, of £10,000 a year. He married Emily Doyle from a distinguished Irish military family; her grandfather, Major-General Sir Francis Hastings Doyle, 1st Bart, was Deputy Lieutenant of the Tower of London. Her brother, by contrast, was Professor of Poetry at Oxford and the author of The Private of the Buffs and other well-known poems.

Their eldest son, Granville Leveson Gower was a squire of Titsey through most of the second half of the nineteenth century. He built St. James's Church at Titsey and considerably remodelled the house and the garden, continuing the work begun by his grandfather William in the 1820s. He fully lived up to the adage that nobody is more interested in genealogy than the second cousin of a Duke. He decorated the house with the heraldry of the Gresham, Leveson and Gower families and over a twelve year period compiled the Genealogy of the Family of Gresham, privately printed in 1883 (he gave a copy to Queen Victoria as a present on her Jubilee in 1887). He was an enthusiastic historian and archaeologist, a fellow of the Society of Antiquaries who wrote many papers on local history and excavated two Roman sites on the Titsey Estate. He was also active in public life, sitting for many years as MP for Reigate. He married Sophia, daughter of Lord Leigh of Stoneleigh Abbey.

Theirs was a very happy marriage and they had a large family of sixteen children. The eldest son Ronald sadly died of diphtheria in his twenties, so Titsey was inherited by the second son Granville Charles who married Evelyn Brassey of the railway construction family. They had four sons, none of whom married. Ronald, the second son, was killed in the First World War while serving with the Coldstream Guards in France. Alan, the youngest, was a major in the Coldstream Guards and a successful breeder and owner of horses. His most successful horse was St.George II which was bred by his father, trained at Titsey and ridden by Alan to victory in the National Hunt Steeplechase at Cheltenham in 1938. Allan died in 1974. Richard, the eldest, was a major in the Grenadier Guards and served in both World Wars and with the third brother Thomas lived at Titsey, restoring the house and reviving the gardens after war-time requisitioning and occupation by Canadian Troops. Thomas, in particular, was a keen gardener. Having no children, the last surviving brothers, Richard and Thomas, appointed David Innes as their heir. Thomas had been appointed guardian to David Innes under the will of his father who had been a close family friend of the brothers and their parents. Together they established the Titsey Foundation to preserve the house and garden and open them to the public, together with the church and parkland.

The Titsey Crest comes from the joining of the two most important families in the Estate's history; the Leveson Gower Wolf and the Gresham Grasshopper with their combined Coat of Arms in the middle