This month I’m hanging out with the Stuarts as I contemplate the Hampshire-born economist, demographer, physician, anatomist, epidemiologist, academic, philosopher, scientist, mathematician, statistician, cartographer, architect, administrator, merchant, musician, inventor, MP, all round polymath and one of the greatest minds of his time, Sir William Petty (1623-87), who was a friend of the famous diarist Samuel Pepys and who’d also be, through his daughter, an ancestor of a Prime Minister, as well as a companion to Kings.

Petty was born in Romsey, third child to Anthony and Francesca Petty, the son and grandson of a clothier, on May 26, 1623, and despite his fairly modest lower middle-class origins, went on to become one of the abbey town’s most famous sons along with Lord Palmerston who may have been born in Westminster but resided in Romsey. There’s a plaque in the town recording Petty’s arrival and departure: ‘Born on the site of this house 26 May 1623 – anatomist, economist, founder member the Royal Society, cartographer, designer – buried in Romsey Abbey 24 December 1687’. He attended Romsey Grammar School but would soon outgrow the town. There are some suspicions that Petty downplayed his origins even further to make his rise from relative obscurity even more dramatic.

Great British Life: Site of Sir William Petty's birthplace in Romsey. There's a plaque on today's building which can be found close to the junction between Church Street and Portersbridge Street. Site of Sir William Petty's birthplace in Romsey. There's a plaque on today's building which can be found close to the junction between Church Street and Portersbridge Street. (Image: Graham Tiller)

Going to sea as a cabin boy in 1637, his life on the waves was curtailed by the virtue of breaking a leg on board, so he broadened his horizons with foreign travel and residence. He studied at a Jesuit college in Caen, but also at Utrecht, Amsterdam, Leyden and Paris, learning medicine, maths and chemistry whilst this country was engulfed in the English Civil War. He didn’t entirely neglect his homeland as he had returned to England by 1646 and hunkered down at Oxford where he took his Doctor of Physic degree in 1649 and became a ‘don’ (fellow/tutor) of Brasenose College in 1650, and taught anatomy from 1651.

His fellowship was eventually declared void in 1659 due to his numerous absences, e.g. in Ireland (below) and his burgeoning private income. Whilst Petty was Reader in Anatomy at Oxford, a macabre event occurred in 1650 which is worthy of mention. The then custom was for Oxford medical students to practice dissection on the bodies of executed criminals and Petty duly took possession of that of Anne Green, hanged for the murder of her illegitimate child. Petty discovered Anne was still alive, however, and he and a colleague revived her; she went on to marry, have three further children, and live another 15 years. Some say Petty’s fame rests partly or even primarily on this single episode which he ensured appeared in print; he was never reticent about bigging up his achievements.

Great British Life: Brasenose College, Oxford, where William Petty became a don in 1650.Brasenose College, Oxford, where William Petty became a don in 1650. (Image: Ozeye)

Petty truly came to prominence reporting to Oliver Cromwell during the Commonwealth and was appointed physician to the army in Ireland in 1652. He engaged in a fresh, efficient, definitive mapping survey of Irish lands with a view to redistribution among Cromwell’s soldiers, supplying the first accurate map of Ireland in the process, as well as beginning ironworks, lead-mines, sea-fisheries and other industrial enterprises on estates he had purchased in south-west Ireland (18,000 acres across five counties). It was Ireland that really transformed Petty and ensured he was returned as an MP in 1659. He sounds quite the entrepreneur after his stint there and perhaps got his reward as he successfully transitioned to the restored monarchy from 1660 when he was appointed surveyor-general of Ireland by Charles II who also knighted him in 1661. His career continued to prosper under Charles’ younger brother who’d become James II. Having made a fortune from his various activities, Petty became a notable figure in the post-Commonwealth, Restoration period, but it was his Irish experience that first got him interested in the forming of public policy and the role economics had to play in this.

Petty was an inventor as well as an industrialist and developed a copying machine (1647) and double-keeled sea-boat (1663), Europe’s first catamaran, even finding time to be professor of music at Gresham College in London, as well as becoming a co-founder of the Royal Society. As far as political economy was concerned he was very much a precursor to the famed Adam Smith, writing a ‘Treatise on Taxes’ (1662) which examined the role of the state in the economy, and ‘Political Arithmetic’ (1676), the latter being a discussion of the value of comparative statistics for he was the first to look at economics in a scientific way, his definition of ‘political arithmetic’ being the ‘art of reasoning by figures on things relating to government’.

Great British Life: Sir William Petty's 'Another essay in political arithmetick concerning the growth of the City of London'Sir William Petty's 'Another essay in political arithmetick concerning the growth of the City of London' (Image: Wellcome Collection)

When Petty’s friend John Graunt set out to try and calculate for the first time the true population of the city of London in 1662 it would be Petty who’d later explain the shift from supposition to statistics: ‘Instead of using intellectual arguments I have taken the course to express myself in terms of number, weight or measure’. He also offered his own ingeniously calculated estimates of population and income. Petty sounds like the kind of man we could do with in Parliament today, someone who understands politics and economics, but who’s also got his hands dirty in industry. We owe much to the advent of statistical thinking during the Restoration period; Petty was very much on the money. If you’ve ever heard the term ‘full employment’ used, well, you have Petty to thank; he was the first to coin that phrase.

Petty married Baroness Shelburne in 1667, his sons successively Lord Shelburne, these being Charles Petty, 1st Baron Shelburne (1672-96) and Henry Petty 1st Earl Shelburne (1675-1751). There was also a daughter, Anne Petty (Fitzmaurice) (1675-1737), and the infant departee John Petty (1669-70). Anne’s marriage into the Fitzmaurice family meant that William Petty would be an ancestor of the 1st Marquess of Lansdowne, another William Petty, Earl of Shelburne (1737-1805), who became Prime Minister 1782-83.

Sir William Petty died on December 16, 1687 in London aged 64. He’d be buried in Romsey’s abbey eight days later on Christmas Eve and would later be honoured with a fine marble effigy, carved in 1848 by Richard Westmacott, where the reclining figure holds a scroll bearing the Royal Society’s seal. Petty’s ‘Economic Writings’ were edited and published by C.H. Hull in two volumes (1899) whilst his life was also written by Lord Edmond Fitzmaurice (1895) which shows there was still a keen interest in his thinking as the Victorian era waned. Petty is best known for his economic theories, including the promotion of a ‘laissez-faire’ approach, and methods of political arithmetic. A collection of his correspondence and papers is held in the British Library.

Great British Life: Romsey Abbey which must have been a familiar sight for William Petty who was born in the town in 1623. Romsey Abbey which must have been a familiar sight for William Petty who was born in the town in 1623. (Image: Romsey Abbey)


1623 – William Petty born in Romsey, Hants (May 26).

1637 – Goes to sea as a cabin boy and promptly breaks his leg.

1650 – Becomes a don of Brasenose College, Oxford, having passed his Degree of Physic.

1652 – Petty’s Irish ventures begin when he’s appointed physician to the army in Ireland.

1659 – Returned as a Member of Parliament at Westminster.

1661 – Transitions successfully under the Restoration and is knighted by Charles II.

1662 – Publication of Petty’s ‘Treatise on Taxes’ as he makes a name in political economics.

1667 – Marries Elizabeth Waller who was given the title Baroness Shelburne for life.

1687 – Death of Sir William Petty in London (December 16) aged 64.