England head to Dublin on Saturday looking to make history on two fronts.
By racking up a 19th consecutive victory - the most by any team against tier-one nations - Eddie Jones' men will become the first side to win back-to-back Six Nations Grand Slams.
But how might Ireland spoil the party in their own back yard? We take a look at where Joe Schmidt might find a way past England.
REDISCOVER CHICAGO SPIRIT
It was Ireland, of course, who halted New Zealand's winning run at 18 in November, producing a stunning display in Chicago.
The American city was already on a high following the Cubs' World Series triumph, and the carnival atmosphere carried into the Test at Soldier Field, where the vast majority of spectators were behind the men in green.
The Cubs had waited 108 years for their triumph and Ireland's victory was their first over the All Blacks in 111 years of trying.
Ireland have been unable to replicate that kind of performance during this year's championship, losing in Scotland and Wales to miss out on setting up a title decider against England at the Aviva Stadium.
But with a fervent crowd behind them on St Patrick's Day weekend, Schmidt's side will be hoping to evoke the spirit of Chicago and deny England a record-breaking day.
TAP INTO FARRELL FAMILY CONNECTIONS
Ireland have one advantage over all of England's opponents to date - Owen Farrell's dad is on the coaching staff.
Andy Farrell joined Schmidt's team as defence coach last year, having previously worked under Stuart Lancaster in the English set-up.
Son Owen has been one of England's most consistent performers and could be an outside bet to captain the Lions in New Zealand later this year, whether he beats Jonathan Sexton to the number 10 shirt or sticks with the inside-centre position he has made his own under Jones.
Farrell has scored 54 points during this year's championship - only Camille Lopez of France has racked up more - and Ireland will hope Farrell Snr's insider knowledge can help quell the threat of the Saracens man.
As for Owen's mum? "She just wants everyone to do well," he said this week.
KNOW THE RULES
Robbie Henshaw was left a little red-faced against Wales on Friday after entering a maul illegally with Ireland heading for a potential match-winning try.
The centre entered ahead of ball-carrier Rory Best with the visitors trailing 15-9, prompting referee Wayne Barnes to blow up and curtail a move that had promised to bring Ireland back into the game.
Henshaw confessed to "not knowing the rules" earlier this week, but such avoidable mistakes against a side like England - particularly one on the brink of history - will not go unpunished.
Atoning for that costly error could be a motivating factor for Henshaw on Saturday - not that the 23-year-old thinks he needs it.
"To end England's winning streak is a great motivation for us," he said.
PULL OFF THE ITALIAN JOB
On the subject of knowing the rules, it is remarkably Italy who seemed to have England most rattled of any team during this year's championship.
Their no-ruck tactics - overseen by Irish coach Conor O'Shea - baffled the would-be record breakers, who sought guidance from the referee over how to handle the alien approach.
Ireland are unlikely to take a similar route. One suspects England would not allow themselves to be so unprepared for such a tactic again.
However, England's first three wins this year - including the one over Italy - were by no means straightforward and prove that there are weaknesses to be exploited in this England team.
Schmidt's job will be to identify any frailty and expose it, even if last week's Scotland demolition job was an ominous warning of what Ireland must expect.