The poet and architectural historian Maurice Craig wrote in a (sardonic) lament for Belfast in 1948: “This jewel that houses our hopes and fears/Was knocked up from the swamp in the last hundred years”. The creation of the Victorian and Edwardian industrial and commercial city of Belfast on its sleechy foundations from about 1850 onwards continues to prompt fascination.

This period of remarkable change coincides with the heyday of one particular, so far largely under-sung, Belfast-based architectural and civil engineering practice which did an extraordinary amount to affect the built appearance of the city: Young & Mackenzie. The firm was a pivotal player in the transformation of the appearance of Belfast in particular, and significant to the architectural landscape of many other Ulster locations too, for at least 100 years.

My recent book Architects of Ulster: Young & Mackenzie – A Transformational Provincial Practice, 1850-1960, published by the Ulster Architectural Heritage Society, documents the work of the prolific practice and also tells the story of three generations of the Young family who were significant historical figures in themselves. The founder, Robert Young, became the first Irish Architect Privy Councillor and his son, Robert Magill Young, was a notable chronicler of Belfast; both were instrumental in developing the cultural life of the city.

The monograph contains more than 600 illustrations – many published for the first time and a large number drawn from the firm’s vast archive at the Public Record Office of Northern Ireland – and features commercial, institutional, domestic and ecclesiastical work by the firm and a comprehensive gazetteer.

Just some of the major Belfast designs include: the former Robinson & Cleaver’s and Anderson & McAuley’s department stores (each with famous impressive staircases originally); the Scottish Provident Buildings; the Ocean Buildings; Belfast Royal Academy; the (now) Crescent Arts Centre (originally Belfast Ladies’ Collegiate School, later Victoria College) and, perhaps most notably of all, the Presbyterian Assembly Buildings (or Church House), with a distinctive copper crown spire, blending Tudor Revival and Scots Baronial architectural styles and built of Scrabo sandstone.

Beyond Belfast, one of the firm’s earliest industrial commissions was the City Factory in Derry, while other educational projects included Lurgan College (originally Watts’ Endowed School) and Rainey Endowed School in Magherafelt – Robert Young was a surveyor in both towns.

The firm’s ecclesiastical output was mostly for Presbyterian congregations, and in addition to “Church House”, Belfast, Young & Mackenzie designed Gothic Revival landmarks such as First Armagh Presbyterian; Cullybackey Presbyterian and Fitzroy Presbyterian in Belfast – all with soaring spires – but in among the large number of buildings, readers will also find the design of Belfast’s Annesley Street Synagogue.

The firm’s domestic work was varied and widespread, including, for example, Lennoxvale House, now the Queen’s University Vice Chancellor’s residence, and the Culloden Hotel, Cultra, which was originally designed for a wealthy stockbroker, Matthew Robinson, and subsequently used as a Bishop’s Palace before becoming the hotel it is today.

In 1907, another Belfast architect, WH Lynn, wrote to congratulate Robert Young on becoming a privy councillor and remarked upon this transformation of the cityscape as he recalled his own experience of arriving as a pupil at Lanyon’s office where he had first met Young: “My dear Young, I congratulate you most heartily on the honourable distinction which I notice has been conferred on you … I am strongly reminded of very old times – March 1844! when you were the first one in Belfast, I may say, that I made acquaintance with. I recollect quite clearly … the Square, and on the promenade where all the belles and the swells of that remote period used to parade, and perambulate round and round the Linen Hall flags at the fashionable hour. Your present office [in the Scottish Provident Building] is not far removed from that old spot, but what an altered condition of things, in every way, presents itself as you look in the same direction now!”

Contemporary “perambulists” of Belfast and other northern towns will, needless to say, discover a built environment much changed from 1907; however, a striking number of Young & Mackenzie buildings from the Victorian and Edwardian eras are still intact, in use and holding their own, if sometimes taken for granted. Into the twentieth century – with the firm operating as a family dynasty under RM Young’s son, Captain James Reid Young, until his death in 1967 – some of the firm’s interesting work included Belfast’s first flat-roofed Modernist house off Belfast’s Antrim Road, the red sandstone Presbyterian Memorial Hostel in Belfast’s Howard Street and the Rosemary Street Masonic Hall, which contains a fine interior with a John Luke mural.

This new book seeks to engage the reader with the rich history of these characterful structures and the history of this prolific and energetic practice which imagined and guided them into existence. Even beyond this, I and the publisher hope to encourage people to value and appreciate Ulster’s built heritage and take building conservation and restoration seriously. Without buildings such as very many of these, communities lose so much of their character and a distinctive sense of place.

Buildings as well as people have fascinating stories to tell and I hope that Young & Mackenzie – A Transformational Provincial Practice will help make these building and the past come alive – that it will interest all kinds of readers, from those who are intrigued by buildings as well as those interested in the history of this part of the island.

Architects of Ulster: Young & Mackenzie – A Transformational Provincial Practice, 1850-1960 is available in selected bookshops and online from the UAHS: uahs.org.uk