He sat at the back of the lecture room doodling and drawing cartoons, She sat near the front; she was a year older than him. Nicholas Robinson was third in a family of four boys from a middle-class Dublin Protestant home, descended from coopers attached to the Guinness brewery. His grandfather had run a coal business. His father, Howard, was an accountant with the City of Dublin Bank and a prominent member of the Masonic Order.

His mother, Lucy, had studied art and was related through her mother to a Dublin sculptor. She had died when Nicholas was only 10 and he was sent to board at Mountjoy School in Dublin city centre.

In college, he began to date his classmate, Mary Bourke, the girl who sometimes wore silk gloves to evening debates. When she took her finals, she secured first-class honours. He scraped through with a third-class placing. She won a scholarship to Harvard Law School in Boston. Through his family connections, he had been offered an apprenticeship with a prominent Protestant legal firm in Dublin, Matheson, Ormsby and Prentice, but thought he might go to London to try his hand at cartoons.

He was known to be clever, but "didn't kill himself", David Norris remembers. Urbane and as distinguished as Mary Bourke in her own way, Nicholas Robinson took an "Olympian view of life". But if he enjoyed himself, he was also regarded as very reliable and stable. It was an obvious attraction for someone taking intellectual risks and pushing out boundaries.

After the finals, there was little time for idleness. Within hours of the last exam, Mary Bourke was on the plane to Boston, over a week late for the start of term. Nicholas Robinson was late arriving at Westland Row to bid her farewell with a single red rose. Nanny Coyne accepted it instead.

The Irish Times carried a two-paragraph single column report: Ireland's youngest senator, it said, would be married quietly to "newspaper cartoonist and artist Mr Nicholas Robinson, of Clare St, Dublin, tomorrow". In December 1970, 26-year-old Mary Bourke was to be wed.

But not in Ballina. Not by the babbling Moy. Not even in Trinity College Chapel, looking out on to the cobbled front square. The "mixed" marriage took place in the rather anonymous church at Dublin Airport, with a few friends and colleagues present. It was a practical choice: there would be an early flight to Paris the next day. They travelled on to Tenerife where they spent their honeymoon in a house owned by Nick's father. None of the Bourke family was there to throw confetti or wave them off.

Over a quarter of a century after that wedding, reports and profiles repeatedly state that the Bourke parents objected to their daughter marrying a Protestant. Those close to the couple are less willing to accept this as the case, and her father denies that this was the reason. He and his sons still regret the decision. Given the family background, complete with Protestant branches, and the quest for a dispensation so that their children could attend Trinity College, Dublin, it would have been surprising if Mary's parents were unable to accept that mixed marriage was a fact of 1970s Irish life.

Was Tessa Bourke a mite disappointed, perhaps, about her daughter's choice? At the time, it looked as if Nick had few prospects: he was drawing cartoons. It was a painful period, and the only serious disagreement that the family had; but it did not last beyond a few months, and wounds were quickly healed through the discreet intervention of Mother Aquinas, Dr Bourke's aunt.

Even as they set off for Spain, the senator was in the news for trying to cut short her holiday. On December 14th, 1970, The Irish Times reported that a "strong protest" would be made by senators when the house resumed the following day over the "extraordinary long recess" of 137 days!

Quoting a recent letter to the newspaper by Senator Bourke, where she had pointed out that the economy could not afford a Seanad that was "merely decorative" in this "time of crisis", the report said that the 60 senators who made up the upper house and were being paid £1,500 a year, were "seriously embarrassed" by the archaic system of parliamentary procedure, which had left them "idle" for more than one-third of the year.

"In a democracy", the young senator had written, "there are sound reasons for retaining a Second Chamber in the legislature, provided it is allowed to play an active role in legislating and debating matters of public interest."

As befitted tradition, the senator took her husband's name. Pressed in an interview much later on to defend her decision to marry so young - though in those days, it was not unusual - she said that, for her, marriage had proved to be "a liberating experience", which had given her the freedom to grow in a happy partnership. Nick, urbane, confident, comfortable at her side, would give an innately shy but ambitious young woman constant support in the social circles she was bound to move in if she was to succeed. It was obviously attractive to have a reliable and stable partner if one was pushing out social boundaries and taking intellectual risks. She would not abuse it. Family life would be kept separate, and very private.