[3] Jones was born at Newland, Gloucestershire[4] and brought up in Monmouth, leaving to make a sizeable fortune as a London merchant engaged in the cloth trade with the continent.

[a][6] The motivations for his bequest appear partly philanthropic and partly evangelical; the county of Monmouthshire in the early 17th century had a significant Catholic presence[7] and the local historian Keith Kissack noted, "the priority given to the preacher illustrates [Jones's] concern to convert an area in the Marches which was still, when the school opened in 1614, strongly recusant".

[4] The bulk of Jones's considerable bequest was used for the purchase of lands at New Cross, in South-East London, and the rent rolls from that estate provided the money for the salaries and running costs associated with the school, as well as the payment of pensions to the residents of the almshouses.

[16] Continuing religious controversy, coupled with the English Civil War, made the town of Monmouth a divided and uncertain setting for the school.

Divisions between staff, and the financial instability, and remoteness, of the Haberdashers Company, which was compelled to make substantial loans to the Parliamentary government that went unpaid for decades, and was then required to finance the rebuilding of their livery hall which was destroyed during the Great Fire of London,[17] contributed to internal weaknesses.

[18] These difficulties continued well into the 18th century, and at one point, during the headship of the "morose and tyrannical" John Crowe, who was removed from his post after becoming insane, the school roll fell to just three boys.

The diary, extracts from which were published in the Monmouthshire Beacon in 1859 but which is now lost, records Pye's experiences in great detail from the date of his appointment in 1646 until his resignation in 1652.

The first issue saw the school perceived as part of the faction of the Dukes of Beaufort, the premier landowners in the county, and directors of the town's politics from their regional base at Troy House.

[24] The school's leadership was perceived in the town to be too close to the Beauforts, and Thackwell ran an almost fifty-year campaign against their attempts to defend the established order.

[27] Reforms introduced by John Oakley Hill in 1852, saw the establishment of Upper and Lower Schools, the former continuing to provide a classical education, while the latter had a curriculum focused on writing and arithmetic.

John Powell", Coxe retells the mythical story of the school's establishment and records a "portrait of the founder, habited in the costume of the age of James the First, with an inscription 'Walter William Jones, haberdasher and merchant of London etc.'

[32] During Roberts's time Monmouth became an early member of the prestigious Headmaster's Conference (created by Edward Thring of Uppingham in 1869), a mark of its increasing reputation and status as a public school.

[36] As a result of rising revenues from rents and investments,[37] by the mid-19th century, Monmouth's endowment was one of largest of any school in England and Wales.

[35] Monmouth School's Combined Cadet Force was reportedly the last CCF in the country to change its uniforms to khaki from the traditional blue at the outbreak of war in August 1914.

[g][42] Blinded by a bullet to the head the following year, he returned to Monmouthshire and worked as a solicitor in Coleford, unveiling the school's war memorial in 1921.

[53] This led to the permanent closure of the school's ceremonial entrance, the Wye Bridge Gate, constructed by Henry Stock in the 1890s.

The direct impact on the school was perhaps less significant, Ward had recorded an early comment on the entrance, "that ancient gate which never opened is but thrice a year on notable occasions, such as when the coal cart comes".

[55] In response, a committee of the Old Monmothian Club, headed by Lord Brecon and Sir Derek Ezra undertook a campaign to raise funding for scholarships which accumulated £100,000 in ten weeks.

[61] In June 2022, the Haberdashers began a consultation on proposals to merge the Boys and Girls schools, making them fully coeducational.

[64][65] The Monmouthshire antiquarian Charles Heath described the traditional, and almost certainly inaccurate, story of the school's foundation in his Accounts of the Ancient and Present State of the Town of Monmouth, published in 1804.

[66] Heath records that William Jones, now established as a successful and wealthy merchant, returned to his home town of Newland disguised as a beggar.

[70] William Jones's original foundation provided for a schoolroom, on the site of the present chapel, houses for the Headmaster and Lecturer, and almshouses segregated by sex.

[82] Snooke's work was not universally praised; a report from the School's Commissioner commenting, "the architect has arranged the buildings in a most inconvenient manner, and the ventilation is deficient.

"[83] School House, with its ceremonial arched entrance and coat of arms facing the Wye Bridge, and the adjacent technology block, were designed by Henry Stock in 1894–1895.

[93] The architectural historian John Newman describes the 18th-century building, situated on the Hereford Road away from the main school site, as "the best house in the entire street".

[76] In 1985–1986, two ceramic murals were designed for the chapel by the Polish religious artist Adam Kossowski, a friend and wartime colleague of the school's Head of Art from 1947 to 1978, Otto Maciag (1918-2000).

Executed by Maciag, and another art master at the school, Michael Tovey,[96] the murals were dedicated at a service conducted by the Bishop of Monmouth, the Rt Rev Clifford Wright on 3 October 1987.

[98] In November 2008, a £2.3 million sports pavilion was completed[99] and opened by the former British Lions player and Welsh captain, Eddie Butler, an old boy of the School.

[95] Further funds came from the Haberdashers' Company, and the first phase was completed with the rebuilding of the Red Lion Block, renamed the William Jones Building.

In addition to rugby, rowing and cricket, the school offers a range of other sports which include soccer, cross-country, tennis, basketball, golf, athletics, swimming, water polo, canoeing, and squash.