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Our 2,768 members have registered
2,405 study surnames with us
and a further 6,120 variant names.

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About the study

The Trethewy One-Name study was started by the late Alan Kent, who set up the Trethewy Society in 1993.

This is a worldwide study of the surname and variants, coming together as the Trethewy Society. The society is now run by Raymond Trethewey and Sally Whiffing, with members from England, Australia, Canada, and the USA.

The aims of the Trethewy society are:-

  • Share information and research into the Trethewy Family
  • to document the trees of all Trethewy name-bearers
  • to verify those trees through DNA testing where possible
  • to gain a better understanding of the early Trethewys and how the different branches may be connected

Variant names

Trethaway, Tretheway, Trethewey, Trethewie

Name origin

‘Dewi’ or ‘David’s homestead’ is the most likely origin. Some of the variants may be explained as the ‘homestead near the grave’ as in Trethevy Quoit and the Tintagel place name. It has been suggested that ‘homestead above/near the water’ may be another possibility. A couple of Trethewy place name locations would fit this.

The Anglo Saxon Chronicle first recorded the place name of ‘Trethewey’ ‘tref daewig’ in St Martin in Meneage in 977 AD. There are now six places in Cornwall called Trethewey:

  • St Neot parish, near Treverbyn and close to the River Fowey
  • St Ervan, near Padstow
  • Ruanlanihorne
  • Germoe
  • St Levan
  • St Martin in Meneage

There are also similar place names such as Trethevey and examples can be found in:

  • The parish of Lanlivery (close to Lostwithiel)
  • St Mabyn (adjacent to Egloshayle )
  • Trethevy Manor (near Tintagel)
  • Lewannick, near Launceston

Surnames didn’t become established until the mid-1300’s. It is possible that names changed as people moved residences. Documentation dating back to the early 1200’s refers to people carrying the name De Tredewi and De Trethewy. One of the earliest references is a deed relating to the Priory of St Andrews at Tywardreth.  This records a grant of Odo de Treverbin, where one of the witnesses was Johanne de Tredeway.

Further early references relate to:

  • 1278 John De Trethewy held lands in Penpell, Trethewy and Polharmon
  • 1279 Henry De Trethewy, accounting for Foweymore Stannary Courts
  • 1311 a John Trethewy was a servant of Treverbyn, aged 54
  • 1325 Henry De Trethewy, Mayor of Bodmin
  • 1333 Henry Trethewy appointed keeper of Launceston Castle and sheriff of Cornwall. In 1334 he is quoted as ‘son of John, son of John’
  • 1354 Robert Trethewy, fellow and Rector of Exeter College, Oxford
  • 1356 Henry De Trethewy
  • 1361 Robert De Trethewy, Priest of East Allington (also referred to as alias Boscaveye later incumbent at Phillack in 1380)
  • 1376 John De Trethewy, Mayor of Launceston and also mentioned regarding an agreement at Pelynt in 1378

Historical occurrences of the name

It is possible that there were several different Trethewy families in the County or that these were branches of a larger inter connected Trethewy family.  The coat of arms with goats and engrailed chevron seems to add weight to this.

A number of Trethewys served as Members of Parliament and Coroners:

  • 1325 - Henry was MP for Bodmin
  • 1382 - Phillip was MP for Liskeard, and also Launceston
  • 1421 - Richard was MP for Liskeard in
  • 1429 and again in 1435 - William was MP for Liskeard
  • 1441- William (of Keverall near Looe) was Coroner 
  • 1455 - Robert was MP for Liskeard
  • 1467 - Thomas was MP for Cornwall and also Coroner  

The early records suggest a cluster of Trethewys around the Lostwithiel, Liskeard and Looe areas.  These are associated with the accounting of the Tin Stannaries and the earldom and later Duchy of Cornwall. They were prominent landowning families, serving as MP’s, Coroners and duties for the crown.  Research shows tantalising connections between these families.  It is inferred that John Trethewy of Treverbyn was William Trethewy’s father and Thomas Trethewy’s grandfather.

J L Vivian’s ‘Visitations of the County of Cornwall’ show a direct link from John and Henry Trethewy to Thomas the Coroner, however the lineage would seem to be more complex.

Despite the earlier uncertainties, recent Trethewys would seem to derive from Thomas Trethewy MP and Coroner for the County in 1467. He was in dispute with the Vivian family of Trelowarren raiding the estate killing a servant and later outlawed. He was later pardoned but set up residence at St Stephen in Brannell in 1472.  The family held seats at Treneague, Trevear, Tregargus and Meledor. Research would suggest that present day Trethewys may have originated from this branch.

Other notable Trethewys:

  • John ‘Jack’ Trethewey of St Stephens was Secretary to Lord Hopton and a consort of Charles II
  • His brother, Lewis Trethewey, was Receiver General and also a consort of Charles II
  • William Griffith Trethewey (1865-1926). A mining engineer whose discovery of the Trethewey and Coniagas mines in Cobalt, Canada, led to him becoming a millionaire. He owned the Trethewey Model Farm in Toronto, which by 1910 had become Trethewey Airfield, hosting the first Toronto Airshow. He was also very interested in his Trethewey ancestry
  • William Thomas Trethewey (1892-1956). New Zealand born sculptor
  • Natasha Trethewey (born 1966). Pulitzer-winning Afro-American poet
  • In 1991 Flight Sergeant Paul Leslie Trethewey was awarded the Air Force Medal for helping to save the lives of 16 crew of the ‘Kartli’ off Prestwick
  • In 2015 Captain Tim Tretheway ‘stepped ashore’ after more than 28 years volunteering with the Mercy Ships - Hospital Ships helping developing countries

Name frequency

According to an ONS database there were the following numbers of surnames in use in England, Wales and the Isle of Man in 2002, when the total population was approximately 59.2 million people. This gives a frequency of 1 in 22,690 or 0.004% of the population

Surname      Count            Ranking 
Trethaway     0

Tretheway     31                68493

Trethewey     538               10737

Trethewie      0

Trethewy      39                59263

Total:            608

According to the 1841 census for England and Wales, there were 464 Trethewys in 1841, when the total population was approximately 15.91 million people. This gives a frequency of about 1 in 33,000 or 0.003% of the population

Surname       Count 
Trethaway     1

Tretheway     84

Trethewey     310

Trethewie      3

Trethewy      66

Total:            464

Distribution of the name

The surname originated in Cornwall, but by the nineteenth century had become firmly established in other parts of the world, including North America, Australia, South Africa and India.

The 1841 census for England and Wales shows where Trethewys (all variants) were living in England and Wales.

County Number  
Cornwall 401  
Devon 29  
Derbyshire 13  
Surrey 9  
Somerset 5  
Yorkshire 4  
Herefordshire 3  
Guernsey 1  
 Total  465  

A further breakdown for Trethewy residents of Cornwall shows the following numbers for places where more than ten Trethewys were living:

Parish number
St Stephen in Brannel 114
St Austell 63
Roche 34
St Dennis 19
Gwennap 14
Newlyn 13
St Hillary 13
Breage 12
St Columb Minor 12
St Mewan 12
Ladock 10


All of the Trethewy (and variants) Birth, Marriage and Death entries from the General Register Office indexes for England and Wales have been recorded for the period between 1837 and 2006. Some of this data can now be found in the Trethewy archive on the Guild website, and more will be added soon (requires registration unless you are a member of the Guild).

Census records for England and Wales for Trethewy (and variants) have been recorded from 1841-1911. Information from the 1939 Register has also been recorded.

A large number of Trethewy wills and parish register records have been collected, particularly for Cornwall.

A number of census, civil registration and other records have also been collected for Trethewys elsewhere in the world, though more research is still being done in this area. A large number of Trethewy family trees have been constructed by Alan with the help of researchers around the world.


The Trethewy DNA project is just getting started, and would welcome new participants.

Do have a look at the Trethewy DNA Project pages: