The names Pat Crossan, Tom Gracie and Harry Wattie do not echo through football history. They are not remembered the way the Manchester United players who died at Munich or the Torino team that perished at Superga have been immortalised as the melancholy embodiment of that most wistful feeling: what might have been. Outside Edinburgh, Crossan and his team-mates have been all but forgotten. They will, however, be remembered today.

No club sacrificed more in the First World War than Heart of Midlothian. Sixteen players from the club joined up, most of them enlisting in the 16th Battalion of Royal Scots, the oldest infantry regiment in the army and nicknamed 'Pontius Pilate's Bodyguard'. Seven members of the first team were killed in action.

This morning a ceremony is being held at the club's war memorial outside Haymarket Station in Edinburgh's West End. The locations on the memorial tell their own story: Loos, Arras, Ypres and, above all, the Somme. The toll the war took on Hearts was the club's finest and most desperate hour and one that places the turmoil surrounding the appointment of Graham Rix into a proper context.

When war was declared in August 1914, the football season was already under way. As men rushed to arms, many questioned why football was continuing.

Parliament debated the question. Letters were written to the press - the Edinburgh Evening News published one, signed 'A soldier's daughter', which suggested that 'while Hearts continue to play football, enabled thus to pursue their peaceful play by the sacrifice of the lives of thousands of their countrymen, they might accept, temporarily, a nom de plume, say "The White Feathers of Midlothian".'

Sir George McCrae, a popular figure in the city, announced that he would raise a battalion himself - the 16th Royal Scots - and boasted, furthermore, that it would be full within seven days. The Hearts players led the way. Sixteen enlisted immediately and a further five were declared unfit to serve. 'McCrae's Battalion', as it came to be known, was the original sportsman's battalion. At least 30 professional footballers enlisted, including players from Hibernian and Raith Rovers as well as Hearts.

The players' service attracted others to the colours. Hundreds of supporters responded to an appeal from manager John McCartney: 'Now then, young men, as you have followed the old club through adverse and pleasant times, through sunshine and rain, roll up in your hundreds for King and Country, for right and freedom. Don't let it be said that footballers are shirkers and cowards. As the club has borne an honoured name on the football field, let it go down in history that it also won its spurs on the field of battle.'

The battalion suffered 229 casualties on the first day of the battle of the Somme with another 347 wounded. That the 16th Royal Scots made greater inroads into the German line than any other battalion that day seems a paltry consolation.

Among the dead was Harry Wattie, arguably the best inside-forward in Scotland. No trace of his remains has ever been found. He had already outlived some of his team-mates: Gracie died in October 1915. Crossan was gassed and never recovered his health before his death in 1933.

It might have been so very different. The 1914 Hearts had begun the season with eight straight victories - a mark unmatched until this season. That record included a comfortable 2-0 victory at Tynecastle over defending champions Celtic. Despite the burden of military training, Hearts retained their lead into 1915, playing what the papers called some 'dainty, dazzling' football, full of pace and panache.

It could not last. On 10 April 1915, the battalion returned from night manoeuvres barely in time for the Hearts players to catch the train to Greenock for that afternoon's fixture against Morton. In such circumstances a 2-0 defeat was unsurprising. Celtic defeated Aberdeen that same afternoon and moved to the top of the table for the first time. The following week Hearts lost again, at St Mirren, and Celtic's 4-0 victory against Third Lanark sealed the title.

An embittered Evening News remarked: 'Between them the two leading Glasgow clubs have not sent a single prominent player to the Army. There is only one football champion in Scotland, and its colours are maroon and khaki.'

Hearts had won 19 of their first 21 fixtures; after New Year's Day, however, distracted and weakened by the rigours of their training, they lost three and drew six of their final 17 matches. It is entirely possible that but for the war Hearts might have established a dynasty in Edinburgh and that Scottish football might have been carved up between three rather than two powers. As it was, Celtic and Rangers' dominance between the world wars was interrupted only by Motherwell's sole championship success in 1932. The Kaiser can perhaps be blamed for the uncompetitiveness of the Scottish league.

As Jack Alexander, author of McCrae's Battalion: The Story of the 16th Royal Scots argues: 'I don't think there can be any doubt that it was the best team in Hearts' history. It was on the verge of becoming a side strong enough to win several championships.'

Apart from a brief spell in the 1950s when Dave Mackay and Alex Young helped them win a brace of championships, Hearts have been also-rans ever since. The 1998 Scottish Cup victory their sole trophy since 1962. This year's side have a lot of history to make up for.

That great side from the Great War is owed more than just a championship. On 22 April 1915, McCartney received a letter from the parents of Private John Williamson Campbell who had died of pneumonia a fortnight earlier. 'Our son,' they wrote, 'had hoped to see his comrades win the league. He was just so pleased to be serving with the Hearts boys. It is so very sad.'

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