Robert Edward Petre, 9th Baron Petre (March 1742 – July 1801) was a British peer and prominent member of the English Roman Catholic nobility. He hailed from an extraordinarily affluent family and devoted himself to philanthropic endeavors. Lord Petre played a crucial role in commissioning James Paine to design a new Thorndon Hall as well as a house in Mayfair.

Early life Lord Petre was born in Ingatestone Hall, about five months prior to the death of his father, who succumbed to smallpox at the age of 29. He was the son of Robert James Petre, 8th Baron Petre (1713–1742), a renowned horticulturist, and Lady Henrietta Anna Mary Barbara Radclyffe. His mother was his guardian until she died in 1760.

His maternal grandfather was James Radclyffe, 3rd Earl of Derwentwater, who was the grandson of King Charles II through his mistress Moll Davis.

Lord Petre inherited an exceptional amount of wealth and influence. Although claims of being one of the twelve richest men in the Kingdom may be exaggerated, his estates were undeniably extensive. His ancestor, Sir William Petre, had acquired approximately , primarily in Essex and the West Country. This land was further expanded by Sir William's son, John, who added a further . Lord Petre's grandmother, Catherine Walmesley, inherited her family's large estates in Lancashire and Surrey, which were reputed to be worth £7,000 per annum at the time of her marriage.

There is a lack of personal writings and correspondence in the Petre family archive and so it is difficult to form a rounded impression of the man; legend has it that, in later life, he himself destroyed many of his personal papers. They bore witness to the acrimonious disputes which he was to have with the Roman Catholic hierarchy and which, in retrospect, he came to deeply regret. It is clear he was no great intellect; one now anonymous commentator is particularly unkind.

His literary equipment fell short even of the moderate standard then expected of a nobleman and his generous patronage of men of letters and art seems to have been dictated by other considerations than intellectual sympathy.

On the other hand, as Charles Butler, lawyer and Secretary of the Catholic Committee of which Robert was chairman, wrote in his obituary, "All his actions were distinguished by rectitude, openness and dignity". Indeed, from the events of his life emerges a picture of a man of great energy, determination and perseverance with a keen sense of patriotism and duty.

Robert's dogged resolve may well have sprung from a stoicism in face of adversity learnt from those under whose tutelage he was brought up, if it is not too extravagant so to characterize an environment as privileged as his. Not only did his mother lose her husband only months after Robert's birth but both her father and her uncle, executed for their parts in the Jacobite uprisings of 1715 and 1745 respectively, and also her brother, killed in a riding accident, had died prematurely. Robert's grandmother, the redoubtable Catherine Walmsley, was also no stranger to tragedy. Both her parents had died by the time she was four and, during the following nine years, her brother and her two sisters succumbed. She had married the 7th Lord Petre but, a year later, he too died of small-Pox, and she was left, at the age of barely 15, a widow with an infant son. She subsequently married Charles, Lord Storton but, when he died in 1753, she became a widow for the second time.

As mentioned above within a few months of Robert's birth, his father died of smallpox at the age of 29 and so Robert succeeded as the 9th Lord Petre. As a minor, he remained, of course, under the guardianship of his mother and it was only as a result of her death in 1760 that he was permitted to take over his estates at the age of eighteen.

Some additions were made to the original Ginge Petre Charity endowment: for example, a further £48 was settled in 1778 from various properties in the area. Chapman and Andre's Atlas of Essex (1777) shows the almshouses as "the Workhouse", and this seems to have been one of their functions, at least until the 1830s.

Robert also devoted himself to a number of other enterprises. He made annual charitable donations of £500, chiefly to Roman Catholic priests and religious orders both in England and on the Continent. He was the first Chairman of the Chelmer and Blackwater Navigation, which was responsible for building the canal connecting Chelmsford to the sea near Maldon. He was a loyal and patriotic man, for at the end of the century, when Britain was at war with France, he raised a company of volunteers from the districts of Ingatestone, Brentwood, and Billericay; the banners of these volunteers were still hanging in Ingatestone Church in 1848.

Catholic emancipation

Robert was a leading figure in the movement for Catholic emancipation, for example, Dr. Alexander Geddes (1737–1802) protégé of Robert, was a Catholic theologian, writer and scholar who was an honorary graduate of the University of Aberdeen and an early Roman Catholic pioneer of biblical criticism and originator of the "fragment hypothesis" of the composition of the Pentateuch. Between the accession of Elizabeth I and the early years of the reign of George I, thirty separate statutes that either forbade Roman Catholics the practice of their religion or deprived them of their rights and freedoms had been enacted. It is true that, by this time, the emphasis had changed; Roman Catholics could at least adhere to their beliefs and even worship discreetly without undue risk to their life or liberty but the legislation, particularly to exclude them from any public office or profession, was still in place and Roman Catholics remained effectively second-class citizens. How it was that at least some 'treacherous' Roman Catholics were left relatively unmolested by the draconian legislation laid against them cannot be considered in detail here, but the Petre family was not unique in this respect. In fact, Mark Bence-Jones, in his recent book The Catholic Families, even goes so far as to suggest that the effects of the Penal Laws were not entirely disadvantageous to the Roman Catholic gentry. Barred as they were from all public office, they were at least spared the risks associated with such ambitions – the heavy cost of 'electioneering expenses' (or, bluntly, bribes) and the dire consequences of a fall from favour – and could concentrate their energies on the management of their estates, which accordingly prospered.

The principal factor, however, which, over the years, helped to protect some Roman Catholic families from the worst effects of the legislation was the simple matter of the personal loyalty and support extended to them by their local community, even by those who might particularly have been expected to point an accusing finger. Indeed, in some places under the patronage of Roman Catholic gentry, there had been an increase in the number of their co-religionists; in the 27 parishes between Brentwood and Chelmsford that were under the aegis of the Petre and the Roman Catholic Wrights of Kelvedon Hall, the population of Roman Catholics rose from 106 in 1625 to 202 in 1706. Even among the common people, loyalty to Rome was not entirely extinct; a national census of 1767 identifies, out of a total population of seven to eight million, 67,916 Roman Catholics, and there is good reason to suppose that this was a considerable underestimate.

Many did defect, of course, but, at the time of the Catholic Relief Act 1778, there were still eight peers, nineteen baronets and 150 gentlemen of substantial property who remained Roman Catholics. In 1766, Thomas Newman, the Vicar of West Horndon, in whose parish Thorndon Hall lay, was required by the Bishop of London to respond to a questionnaire on the number of Roman Catholics in his parish. He reported:

The truth of the matter was that Thorndon Hall contained a private chapel consecrated by Robert's cousin, Bishop Benjamin Petre in 1739, and the Visitation of Essex conducted by the Roman Catholic Bishop Richard Challoner in 1754 discovered a congregation of 260 there: indeed, in that year alone, 41 had received the sacrament of Confirmation.

Accordingly, restoring to Roman Catholics their rights and liberties, as citizens became Robert's mission. There were very real obstacles to overcome. The continued existence of the Penal Laws was not just a result of bigotry and intolerance. It was years since any supposed heresy or blasphemy in Roman Catholic dogma or liturgy had been an issue but the question of the nature and extent of the allegiance that Roman Catholics owed to the Pope and his temporal 'power over princes' was another matter. There were a number of venerable constitutional precedents to suggest that the English throne did indeed lie within the gift of the Pope – King John had ‘ransomed’ his crown from the Holy See for one thousand marks – and, even if that were not the case, it was widely perceived that, such was the moral authority of the Pope over his flock, that, if he was to command them to dethrone a heretic ruler, they would be obliged to obey. Moreover, any promise a Roman Catholic might make to the contrary would be null and void since it was no sin to break faith with a heretic. Such a perception was perfectly justified for it was in those very terms that Pius V had issued his Bull of Excommunication against Elizabeth I, declaring that she was.

The Vatican had slightly modified but never withdrawn this Bull. The task of Robert and his fellow Roman Catholics was, therefore, to find a way of persuading his sceptical compatriots that they did not recognise the authority of the Pope in temporal matters and that, whatever Rome might say, their allegiance to King George was unequivocal. As late as 1771, Bishop James Talbot appeared in the dock at the Old Bailey charged with "exercising the functions of a Popish bishop", albeit the authorities regarded the trial with some embarrassment. Even if, in practice, the laws were no more than an inconvenience, they were a source of great distress and frustration to one with Robert's sense of patriotic duty. It was for that reason that, in 1771, Robert became a Freemason. Not only did this give him access to many influential figures in the Protestant Establishment but it was, in itself, a snub to the authority of Rome. As recently as 1738, Pope Clement XII had issued a Bull excommunicating Catholics who took part in Freemasonry, a judgment reiterated by his successor, Benedict XIV, in 1751. By a quirk of Canon Law, Robert's apparent defiance of these rulings was only a gesture. Since there was then no official Roman Catholic hierarchy in England, the Bulls could not be formally proclaimed and were not therefore binding. Nevertheless, it was a gesture that was evidently much appreciated; only a year after joining the brotherhood, in 1776, he was elected Grand Master, a position that he held until 1777.

The most practical contribution that Robert made to the cause of Catholic Emancipation was his chairmanship of the two successive committees of Roman Catholic laymen formed to lobby the government and negotiate means by which the disabilities enshrined in the Penal Laws might be swept away. It fell to Robert to take the role as senior Roman Catholic layman in this way since, of the two Roman Catholic noblemen who outranked him, Charles Howard, 10th Duke of Norfolk was a scholarly recluse who rarely left his garden at Greystoke Castle in Cumberland and the 14th Earl of Shrewsbury also had no taste for public life – even though two of the four Apostolic Vicars who administered the Church in England were his brothers.