When the Edinburgh Gunners, as they were know then, beat the Warriors on September 30, 2005, barely 2,500 turned up at the home of Scottish rugby. Last Sunday, almost 24,000 flocked to BT Murrayfield - one third more than attended the Hearts-Celtic match at Tynecastle the previous day.
The few have become a multitude, a record-breaking one in the Guinness PRO12.
Nobody knows how many, or how few, turned up for the opener in 1872 but it is safe to say that no derby occasion has increased its box-office appeal on such a scale.
Over ten years, the numbers for the Warriors' annual visit to Edinburgh have kept rising on the steepest of upward curves. The figures for derby-day at BT Murrayfield are worth pointing out:
September 2005 - 2,502.
September 2006 - 4,342.
Christmas 2007 - 6,225.
Boxing Day 2008 - 12,534.
Boxing Day 2011 - 13,246.
January 2, 2015 - 15,810.
December 27, 2015 -23,642.
And how Edinburgh's players rose to the splendour of the occasion, producing a performance worthy of their attendance. The winning margin, 23-11, left the Warriors licking the wounds of their heaviest defeat since clinching the Guinness PRO12 title in such exhilarating fashion against Munster in Belfast at the end of May.
Tries either side of half-time from Matt Scott and John Hardie ensured that Edinburgh finished the first half of the holiday double with one hand clamped on the trophy. It had been under lock and key in Glasgow for four years until Alan Solomons' squad wrenched it back last season by an aggregate margin which could hardly have been much closer - 26-24.
Not for nothing does the veteran head coach consider the all-Scottish affair to be 'one of the big derbies of world rugby.' Judging by last weekend's support, it's getting bigger season by season and Saturday's return at a packed Scotstoun has all the makings of a humdinger.
The attendance will be nowhere near last Sunday's but a full house on Clydeside will generate a Hogmanay passion befitting the importance of the occasion. Whichever way it goes, the ripples will extend far beyond Scotland, south to Wales and across the Irish Sea as seven teams fight it out for the top-four play-off zone.
In denying the champions the consolation of a losing bonus point, Edinburgh fortified their enviable reputation as the misers of the Guinness PRO12 when it comes to conceding tries. In ten matches this season, they have let through just ten - one fewer than Ulster and Leinster and a great many fewer than everyone else.
The cumulative reward for that is to be found in the table. Not for nothing are Edinburgh up to fifth, two points and two places above the Warriors who do have a game in hand. Head coach Gregor Townsend knows that will not count for much should the holders start 2016 the way they started 2015, losing to Edinburgh, again.
The rising box-office appeal of both Scottish teams contributed to Round Ten reaching an aggregate attendance of more than 82,000 for the six derbies, an average of almost 14,000-per-match. Four of them were in the balance until the very end.
Scarlets-Ospreys set the tone on Boxing Day before a capacity crowd of 14,568 in Llanelli, a 53-point thriller which the Ospreys won by the narrowest possible margin. They did so not just because of Moldovan prop Dimitri Arhip's turbo-charged blindside dash for Eli Walker's seventh try of the season but, in the end, because of Stephen Shingler's last-minute penalty miss.
Despite losing for only the second time this season, the Scarlets stay out in front, one point clear of Connacht. They, too, had to settle for nothing more uplifting than a home losing bonus point, Ireland's leading challenger having been beaten in Galway for the first time since last May.
In denying their opponents an eighth straight home win as well and leaving them with a blank on the try sheet for the first time since February 2014, Ulster hauled themselves into the top four.
Just as Nick Williams' late try made all the difference in Galway so Dries van Schalkwyk's for Zebre in Parma prevented Benetton Treviso from ending their long wait for a win. Instead, the No. 8's fifth try of the season left Treviso wondering what might have been after matching Zebre try for try.
While Treviso came from 13 points down and almost turned their match upside down, the Dragons lost an eleven-point lead in the course of losing at home to the Blues for the second festive season running. Rhys Patchell's high-pressure late penalty enabled the Blues to make the short journey home to Cardiff with their first back-to-back wins of the campaign.
As with the first Welsh derby 24 hours earlier, there was only one point in it.
The Guinness PRO12 reaches the halfway stage on New Year's Day with two more all-Welsh affairs.
The Dragons, restricted to nothing more than a solitary point from their five away matches, face the Ospreys at Swansea while the Scarlets travel to the BT Sport Cardiff Arms Park in defence of their position as Guinness PRO12 leaders.
Leinster could conceivably jump from third place to top at the expense of Connacht at the RDS Arena, where no visiting team has won in this competition since the Dragons did the trick almost twelve months ago.
Munster, beaten in their last five matches, seek redemption in Belfast on Saturday against an Ulster squad in the midst of a four-match winning run, including the famous Champions' Cup double over Toulouse. The final fixture of the round on Sunday affords Treviso the chance of avenging their late setback against Zebre.
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