By Andrew Leci
The Manchester Ship Canal was completed in 1894.
This may seem like a strange way to start an article about an upcoming football match, but the historical fact goes a long way towards understanding what has become one of the most compelling, enduring and bitter rivalries in English football.
Throughout the 19th Century, Manchester had become renowned for its manufacturing prowess, while Liverpool was a major port, with an estimated 40% of the world's trade passing through it.
After the completion of the Manchester Ship Canal however, ships could bypass Liverpool and go directly into Manchester, resulting in reduced revenues for Liverpool merchants, the loss of jobs at the port, and a great deal of resentment.
The city rivalry has continued to this day, and is rarely more manifest than in clashes between the two football teams, who just happen to be the most successful in English football history.
Saturday sees the renewal of hostilities between Liverpool and Manchester United, and the backdrop could hardly be more compelling.
Manchester United's Barclays Premier League title last season, took their overall total to 19, one more than Liverpool, with Sir Alex Ferguson finally knocking the Anfield side off the "perch" he so colourfully referred to back in 2002.
Before Sir Alex won his first league title with Manchester United in 1993, Liverpool had completed the last of their 18 (in 1990). It's not surprising then that Ferguson described overhauling Liverpool's total as the "greatest challenge" in his managerial career. When Sir Alex took the reins at United, they had won only 7 titles.
While the 1980s belonged to Liverpool, the 90s and 2000s very much belonged to United, as they picked up the 12 Premier League titles required to supersede Liverpool's achievements. The perch now belongs to Manchester United, and Sir Alex Ferguson is enjoying every minute of it.
To give you an idea of the intensity between the rivals, Steven Gerrard, apparently, despite keeping innumerable swapped shirts in his memorabilia cabinet, refuses to have a Manchester United jersey in his home.
Gary Neville described scoring the winning goal at Anfield and celebrating under the Kop as a "lifelong dream", after John O'Shea had done just that in 2007, and it's interesting to note that while a handful of players have represented both clubs, no one player has been transferred directly between the two since 1964.
What will also be fascinating about Saturday's clash is the renewal of managerial rivalries, as Sir Alex and Kenny Dalglish prepare to lock horns once again.
Theirs is, according to Ian Herbert writing in The Independent, "a rivalry of respect, fury and friendship", and despite its intermittent nature, remains one of the most abiding in English football - ironic perhaps, seeing as both men hail from Glasgow.
It dates back to 1969, and an Old Firm (Celtic versus Rangers) reserve match.
An 18 year old Dalglish, at the start of his career, was deployed at centre-back to mark a 28 year old Alex Ferguson, then at the twilight of his.
Dalglish claims that he had the striker ‘in his pocket' for the entire game, helping his side to a 2-0 win, while Ferguson claims that he remembers scoring in the match. Ferguson's verdict on Dalglish after the match; "That wee fat boy won't make a player." If Sir Alex has been right about most of the assessments he has made in his managerial career, I think we can all safely say that he got that one wrong.
While the relationship between the two has often resembled a feud, there is no questioning the respect they hold for each other, and the delight they both take when pitting wits.
Sir Alex Ferguson is resident on the perch at this moment in time, a fact that will certainly not be lost on Kenny Dalglish. The Liverpool faithful will need no reminding of the fact that their last league title was claimed back in 1990, and Saturday's game could well be an opportunity to lay down a marker in the latest instalment of the great North-West rivalry.