Ireland's history of two Grand Slams leaves them in 'Paddy Last'.
England lead the way on 13, followed by Wales on 11, France on nine and even Scotland on three.
For those who have completed the sweep there is a legacy of greatness, perhaps inflated by the failure of others to follow suit.
As Joe Schmidt said last week, "what is rare is beautiful" and Grand Slams are about as rare around these parts as miracles.
Yet, it took the miracle of Jonathan Sexton's drop goal in Paris to begin the conversation Schmidt refused to have for the six weeks.
Now that France, Italy, Wales and Scotland have been man-handled and The Championship sealed with one round to spare, it is fine for those outside Carton House to dream the dream. It is up to those inside the bubble to make it happen.
In the past, these nerve-wrecking days have not always gone to plan, Ireland winning two, losing two and drawing one.
1948: IRELAND 6 Wales 3, Ravenhill
For so long, this was the one and only Grand Slam, hoisted onto a pedestal as a stand-alone achievement for 61 years.
The central characters were Old Belvedere hooker Karl Mullen and Queen's University out-half Jack Kyle.
The foundation for the sweep came in France (13-6) on New Year's Day at Stade Colombes, the tries coming from wing Barney Mullan and flanker Jimmy McCarthy.
A one-point win at Twickenham (11-10) was underpinned by three tries from centre Des McKee, flanker Bill McKay and Kyle.
The expected defeat of Scotland (6-0) set up a day of destiny in front of a 30,000 crowd.
"We decided on a policy of seeking to win through our forwards and the genius of Jack Kyle," revealed captain Mullen.
The winning try came from Chris Daly, who was later carried high from the field, the shirt ripped from his back.
IRELAND: J Higgins; B O'Hanlon, W McKee, P Reid, B Mullan; J Kyle, E Strathdee; J Daly, K Mullen (capt), A McDonnell, C Callan, J Nelson, J McKay, D O'Brien, J McCarthy.
1951: Wales 3 IRELAND 3, Cardiff Arms Pk
The Irish made their way to Cardiff with six starters from 1948 still on board, including Karl Mullen and Jack Kyle.
Just as importantly, the robust back-row of McKay, Jimmy McCarthy and Des O'Brien remained in place.
The scoring system of the day meant a penalty held the same value as a try, three points, and Ben Edwards kick was neutralised by a typically tremendous Kyle try in the first quarter as the game regressed into a stalemate.
Ultimately, it was sufficient to give Ireland the Five Nations championship, but neither the Triple Crown or Grand Slam.
IRELAND: A McMorrow; W Millar, N Henderson, R Chambers, M Lane; J Kyle, J O'Meara; D McKibbin, K Mullen (capt), J Smith, J Nelson, J Brady, J McKay, D O'Brien, J McCarthy.
1982: France 22 IRELAND 9, Parc des Princes
There had been a break of 33 years since the previous Triple Crown had been annexed, proof of the failure of Ireland to achieve.
The 'Lanigan's Ball' stepping in and out of Ollie Campbell and Tony Ward, since the controversial 1979 tour to Australia, continued as Campbell took back the number ten shirt.
The Old Belvedere fly-half was the main driver in Ireland taking out Wales (20-12), England (16-15) and Scotland (21-12) to dominate the home nations.
The flooding of Lansdowne Road by swarming thousands revealed the depth of the meaning of the match.
One month later, the Irish made their way to Paris without a win there in ten years.
The loss of number eight Willie Duggan on the eve of the match was the opportunity the French pack took advantage of, Serge Blanco striking for one of their two tries, to leave Ireland holding a championship, but no Slam.
IRELAND: H McNeill; T Ringland, M Kiernan, P Dean, M Finn; O Campbell, R McGrath; P Orr, C Fitzgerald (capt), G McLoughlin, M Keane, D Lenihan, F Slattery, J O'Driscoll, R Kearney.
2003: IRELAND 6 England 42, Lansdowne Road
The advent of professionalism had suited the Irish provinces with Ulster winning the 1999 European Cup and Munster making the final in 2000 and 2002.
It was the beginning of what would turn into a golden generation of success for the provinces Munster (2006 and 2008) and Leinster (2009, 2011 and 2012) combining for five European Cups in seven years.
Ireland had looked sharp in buckling Scotland (36-6), Italy (37-13), France (15-12) and Wales (25-24) to set up a winner takes all Grand Slam decider at Lansdowne Road.
It was a step too far as the greatest English team in their history took Ireland's early adrenalin rush and responded with lethal precision.
It was the watershed moment that infused coach Clive Woodward's men with the belief that would take them to World Cup glory in Sydney later that year.
IRELAND: G Murphy; J Bishop, B O'Driscoll (capt), K Maggs, D Hickie; D Humphreys, P Stringer; M Horan, S Byrne, J Hayes, G Longwell, M O'Kelly, V Costello, A Foley, K Gleeson.
2009: Wales 15 IRELAND 17, The Millennium Stadium
The bridge of 61 years from Ireland's first Slam to their second was finally crossed.
At this point, Munster were the dominant force in Europe on the trail of a third European crown in four years.
It was the same season in which Leinster would take over the mantle from Munster to capture three in four.
The growing sense of something wonderful happening was based on beating France (30-21), Italy (38-9), England (14-13) and Scotland (22-15) to set up a dramatic climax in Cardiff.
Ireland were in a 6-0 hole from a tense first-half before Brian O'Driscoll chiselled a try from one metre and Tommy Bowe grabbed Ronan O'Gara's precise cross-field kick to temporarily wrestle control for two tries in three minutes.
The Welsh nibbled away at the lead until Stephen Jones edged the ahead 16-15 with time of the essence.
It all came down to Ronan O'Gara's 77th minute drop goal and Stephen Jones' missed kick
IRELAND: R Kearney; T Bowe, B O'Driscoll (capt), G D'Arcy, L Fitzgerald; R O'Gara, T O'Leary; M Horan, J Flannery, J Hayes, D O'Callaghan, P O'Connell, S Ferris, D Wallace, J Heaslip.