If you look at almost any major restoration project in Oxford, particularly in the University heartland of the city, there is an even chance that the name Symm will be emblazoned across the scaffolding.

What many people may not realise is that the company's origins go back nearly 200 years, and in that time its builders and craftsmen have made a significant contribution to the creation and preservation of Oxford's architectural heritage.

Many of the city's most treasured buildings - notably the Sheldonian Theatre, Bodleian Library, Christ Church Cathedral and Tom Tower - owe their survival to Symm and Co.

The firm's founder, Daniel Evans, was born in 1769, but little is known of his early life. He is believed to have been born in Fairford, Gloucestershire, making his first acquaintance with Oxford as an apprentice upholsterer.

He also seems to have spent time in London, where he apparently worked as a bricklayer, although where and when he learnt his trade is not known.

His conversion to Methodism at the turn of the century resulted in his first major commission - the building of a Wesleyan Chapel in Leicester, to designs by architect and Methodist minister the Rev William Jenkins. Soon afterwards, the Oxford Methodists asked Jenkins to design a similar chapel for their newly-acquired site in New Inn Hall Street, and Evans was the obvious choice to undertake the building.

He completed the new chapel in 1817, at a cost of £2,965 (roughly equivalent to just under £180,000 today), and instantly established a reputation locally for his supreme craftsmanship.

A series of commissions from Magdalen College swiftly followed, starting with the building of the new Magdalen Hall in Catte Street (now Hertford College).

The foundation stone was laid on May 3, 1820, and the building was completed two years later. The twin blocks were designed by William Garbett, surveyor to Winchester Cathedral, and their rather forbidding frontage was denounced by one local as "a barbarous modern building".

Over the next four years, Evans was engaged on extensive building and restoration work on the main Magdalen College site, including renovation of the 15th century chapel, the cloister quadrangle and the dining hall, interior refurbishment and alterations to the library, and the addition of new wings in 1824.

The work on the cloister quadrangle found Evans caught up in a bitter controversy between various senior members of the college, resulting in the unauthorised demolition of the entire north front in August 1822.

Although he was acting on Fellows' instructions, Evans was directly implicated in the College History: "The work . . . hastily pushed on by a builder employed by the College, without full authority, was stopped . . . for some time the College was the battleground of contending architects who poured forth more or less impossible designs for rebuilding, altering or completing this, and other portions of the building."

In the end, it was London architect Joseph Parkinson whose designs were approved for the north and east cloisters, but it was the last contract he was awarded in Oxford. Evans, on the other hand, seems to have emerged from the episode with his reputation intact.

Over the next couple of decades, he continued to work on various projects within the University, including alterations to Merton College Chapel, the building of the Broad Street frontage of Exeter College, and extensive renovations and modifications to Pembroke College buildings.

Other notable projects during this period included the building of Nuneham Courtenay Rectory in 1824, the Radcliffe Asylum in 1833 (now the Warneford Hospital) and Nos 20-22 St John Street, as well as restoration work at St Aldate's Church, Great Tew Church and Great Haseley Church.

In 1829, he completed a row of three terraced houses in St Giles, one of which - No 34 - became his home. He established a builder's yard just beyond his back garden, facing onto Little Clarendon Street, which gave him room to store materials and to stable horses.

The elegant, three-storey, richly-decorated buildings, faced with Bath stone, were deliberately designed to be an eye-catching advertisement for Evans's skills.

In 1840, Evans invited his son-in-law, Joshua Symm, to become his partner, and it was Evans and Symm who completed the substantial modifications to the chapel quad at Pembroke College in 1846. It was Evans's final gift to Oxford. He died in November that year, paving the way for Joshua Symm to take over the running of the company.

For over 20 years, Symm enjoyed a harmonious relationship with the architect Sir Gilbert Scott, and together they undertook a number of significant projects at Exeter College, University College and Christ Church.

One of the pinnacles of their achievement was the new Exeter College Chapel, built between 1856 and 1859, after the old chapel had been condemned as undersized and dangerous.

Scott's design was inspired by the Sainte-Chapelle in Paris, and its most remarkable features are the statues that adorn each of the tall, narrow buttresses, the ornate stone and wood carving, and the distinctive tower that is plainly visible from Broad Street and Ship Street. The interior is quite spectacular, with its soaring, stone-ribbed vault, magnificent stained-glass windows, and the eye-catching tapestry designed by William Morris and Edward Burne-Jones - both undergraduates at Exeter while building was in progress.

Symm's work at Christ Church - which included the building of new student accommodation, as well as restoration of the cathedral - brought him into contact with Dean Liddell, now chiefly remembered as the father of the Liddell girls, who inspired Lewis Carroll's Alice in Wonderland.

By the time Symm died in 1887, at the age of 78, he had passed the reins to a gifted young stonemason, Thomas Axtell, and another trusted associate, Benjamin Hart, who continued to carry out work in and around Oxford to the same exacting standards set by Evans and Symm.

A blue plaque was placed at 34 St Giles in 2004, in lasting recognition of the role Evans and Symm played in helping to shape Oxford's architectural heritage.

But perhaps their most lasting memorial is their company, Symm & Co Ltd, which continues to flourish, ensuring the survival of Oxford's most treasured buildings for future generations.

With thanks to Malcolm J Axtell, great-grandson of Thomas Axtell and current chairman of Symm & Co Ltd, and to Yvonne Macken of Design Fusion for the historic photographs Further reading: Building Oxford's Heritage by Brian R Law (Prelude Promotion, 1998) ISBN 0 9532873 0 0