PASSING the time at Glasgow's newer bus shelters, you might turn round and notice a series of red squares on the otherwise clear plastic backs which have etched on them a tree, a bird, a bush and a bell.

If you are not from Glasgow, you might assume this is a helpful I-Spy game to pass the time before the relevant vehicle hoves into view.

Glaswegians will vaguely sift through their memories to recall it has something to do with St Mungo, the city's patron saint, and a rhyme you might have heard at primary school about the bird that never flew, the tree that never grew, the bell that never rang, and the fish that never swam.

So that's St Mungo summed up, you might surmise - a dodgy poem and some bus shelter decorations.

But it was Glasgow Cathedral's Minister Dr Laurence Whitley who set me straight at the St Mungo Festival in Glasgow at the weekend, who explained that Glasgow as a city might never have developed if it wasn't for St Mungo, even though he was already dead by the time he came to Glasgow's aid.

So this is what happened, if I follow Dr Whitley correctly. St Mungo in the late sixth century helped found Glasgow, but some 600 or so years later it was still only a village clustered around the High Street and Saltmarket. Its rival village Govan, down the River Clyde a bit, was faring better due to having a ford. So what could Glasgow do about that?

Step forward the Cistercian monk, Bishop Jocelyn of Glasgow, who reckoned it was time to put St Mungo to good use. So he hired another Jocelyn, a monk in Furness, to write the history of St Mungo, with lots of miracles thrown in to prove his sainthood. Now Jocelyn was a hack - nothing wrong with that, I hasten to add - who could turn out a good yarn. His book Kentigern De Vita Sua - Mungo confusingly also had the name Kentigern - was a cracker, as Jocelyn the hack had gathered all the tales and legends of Mungo without questioning any of them and producing a great read, albeit in Latin.

There have to be miracles, of course, as otherwise you couldn't be a Saint, so the tales were told of trees being set on fire by Mungo - he might have nicked that one from the New Testament - restoring life to a pet robin, and even finding a queen's ring inside a salmon so that the king would not find out about her adultery. Phew! There are books today that would love to be that racy.

I think there was also a yarn about a cow being brought back to life, but as ungulates are not as photogenic as robins, it rarely gets a mention.

So this was public relations on a grand scale, before the words public and relations were put together by avaricious spin-doctors.

It reignited interest in St Mungo. Glasgow became a site of pilgrimage, religious tourists flocked to the town, old Bishop Jocelyn beavered away fending off Edinburgh and York to make Glasgow important in a religious sense, and for a while a pilgrimage to Glasgow was just as popular as a pilgrimage to Rome. Govan by now was nowhere at the races.

They even had the body of St Mungo, they think, entombed at Glasgow Cathedral, and there's nothing a pilgrim likes more than a relic or two.

Glasgow, as St Mungo so wisely said hundreds of years earlier, flourished. So it's good that the old chap is still remembered annually at this time of year with a modest series of lectures and events.

On Saturday at the Mitchell Library Dr Whitley, and the city's Catholic Archbishop Philip Tartaglia, read extracts from Jocelyn's De Vita Sua, with the Church of Scotland minister favouring an English translation, while the Archbishop happily and fluently stuck to the Latin. All those Tridentine Masses weren't in vain then.

Even having the book there is a tale in itself. At the Reformation, the Cathedral lost many of its religious tracts and books as the Protestands and Catholics played tug of war over who ran the Cathedral. No copies of Kentigern's pot-boiler remained.

But over in Armagh in Northern Ireland, Archbishop Narcissus Marsh had let it be known that he was always in the market for a religious book or two, and he bought a copy. The Marsh Library is now in Dublin, and the curators there were happy to let Glasgow get a copy. It cost a few quid, as we're not talking about simply bending the book open over a photocopier, but Cathy McMaster, then a councillor, helped get interested parties in the city to come up with the cash to make authenitic replicas of the book.

By a stroke of good fortune, an American scholar, Cynthia Green, had painstakingly translated the book into English for her PhD, and copies of that are also available at the Mitchell for those of us whose Latin didn't get much further than "amo ams amat".

The faithful copies of the original still show the little cartoons of a pointing finger which were added by the scribes to show the bishop where the interesting bits were when he was reading from it. It was known as the bishop's finger, a name now used as a brand of ale from Kent.

Incidentally, Mungo's mum St Enoch, apart from having a railway station and a shopping centre named after her, was thrown off a cliff when she refused to say who the father of her then unborn child was, but miraculously lived.

So, even then, unmarried mothers were getting a hard time from the authorities. Some things never change.