There is no more heavily-thumbed, dog-eared, battered book on my shelves than A History of Wales by John Davies. Whenever I need to further my knowledge or understanding of Welsh history, Davies’s definitive account is always my first port of call. Unquestionably far superior to all previous narrative attempts to chronicle Wales’ fiendishly complex saga, it is unlikely to be bettered for years to come. Not only did Davies paint the big picture, acutely identifying and explaining the seismic shifts and sweeping undercurrents affecting Wales across 8,000 years of time, he also unpicked and analysed the multitude of minutiae that have coalesced to form today’s Wales on virtually a village by village basis, and, to put the cherry on the cake, he served up this gift to the nation across 700 pages of meticulously poised, superbly organised and densely involving prose.

That alone would be achievement enough in any life. But John Davies also wrote Cardiff and the Marquesses of Bute, still the single most important study of Cardiff’s history, even including my recent effort (!), and he edited the magnificently exhaustive, every-home-should-have-one Encyclopaedia of Wales, and he was a founder of the Welsh Language Society, and he was a brilliant history broadcaster in both languages, twinkling with natural enthusiasm, wry humour and unpretentious intelligence in ways that couldn’t be imagined by the Schama/Starkey/Snow roster of posh English telly-dons as they smugly dumb down to the hoi polloi from on high, gurning and gesticulating to camera and rubber-stamping the status quo.

You cannot be a decent human being and a serious Welsh historian without also being a Welsh ‘nationalist’ – simply because even a cursory investigation of the past quickly reveals the grievous and multitudinous wrongs done to Wales, wrongs that remain to be righted. Therefore John Davies was, of course, a proud, unequivocal advocate for Welsh independence, as the valedictory final sentence of A History of Wales makes clear: “This book was written in the faith and confidence that the nation in its fullness is yet to be.” His passionate belief that Wales is a work in progress, a project for the future and an entity with validity and importance in its own right ran completely counter to the prevailing propaganda onslaught of the British-Wales establishment – the cradle-to-grave indoctrination that insists Wales cannot come into being to join the global family of nations and must instead remain just a hollow simulacrum selling replica rugby tops. And his sophistication, cosmopolitanism and internationalism made him a standing rebuttal of the old slander that Welsh nationalism is simplistic, narrow and parochial. How he pulled off this difficult trick of being anti-establishment while operating within establishment circles can only be explained by the inarguable power of his perceptions and his irresistible personal charm.

I knew him slightly, first encountering him over 15 years ago in the literary salons of fin de siècle Caerdydd (ie: the Golden and the Kings on a wet Friday night). In real life he was even more convivial, funny and engaging than he was on TV, and he seemed genuinely interested when I droned on about what were then pie-eyed plans to write about Cardiff. Now I look back, I’m astonished at my impertinence in mouthing off to the Greatest Living Welshman (and world’s leading authority on Cardiff) in such a glib, drunken way. John’s generous spirit and luminous humanity meant he patiently put up with my tuppenny-ha’penny tub-thumping, and he always remembered to ask how my book was going whenever our paths crossed.

The loss to Wales is immense. With hindsight, John Davies was the pinnacle of a golden generation of 20th century Welsh historians, alongside JE Lloyd (1861-1947), Wynford Vaughan-Thomas (1908-1987) and Gwyn Alf Williams (1925-1985). The question arises over who in the 21st century will fill the gaping vacancy now left in Welsh public discourse. I’m not worried: John Bwlch-llan knew that the destiny of Wales was ultimately in the hands of the people of Wales. He planted many seeds and some are already beginning to flower. Hwyl fawr brawd.

A celebration of the life of John Davies takes place at City Hall, Cardiff, on Friday April 17 at 5pm