If captains are rated by their ability to deliver rousing team talks or make inspired tactical decisions, Alastair Cook may be remembered as an also-ran.

But if they are rated by their ability to lead by example, to create a relaxed dressing-room environment and instil a shared sense of purpose, he should be remembered much, much more positively.

The simple facts are these: Cook inherited a divided side (he assumed the captaincy at the end of the 2012 English season in the immediate aftermath of Textgate) and led them to two Ashes victories, overseas wins in India and South Africa (no other England captain has managed that) and, only a few months ago, the brink of the No. 1 Test ranking. It is a record that demands respect.

His finest moment may well have come near the start of his reign. The series victory in India - England's first for 28 years - was testament not just to his outstanding batting but his outstanding leadership. By insisting that Kevin Pietersen was reintegrated to the team despite considerable opposition, he ensured he had the tools to overcome conditions in which England historically have struggled. While other victories might have an element of mitigation to them - the South Africa side of 2016 was in decline, the Australian teams of 2013 and 2015 were modest and confronted by conditions that provided England with every advantage - that success in India remains among the high points of England's history.

Cook's batting was at its best in those days. Unburdened by events that lurked round the corner, he made five of his 10 Test centuries as permanent captain in his first nine Tests in the role. His remaining 48 matches brought only five more.

That relative decline was almost certainly due to some extent to the fallout from the Pietersen affair. Whatever the rights and wrongs of the debacle, the scars inflicted in those days were never allowed to heal entirely. Alongside the reasonable coverage, Cook was subjected to a level of criticism - abuse might be a more accurate word - that permanently coloured his relationship with some aspects of the media and appeared to cloud his mind as a batsman. Few would dispute the episode could have been handled better by all involved. It still seems unnecessary.

Cook's stoicism in those days was admirable, though. While he later admitted he had considered resigning (most keenly after a poor performance against Sri Lanka in Leeds in 2014), he retained the support of his team and felt - with some justification - that he was the best option available at the time. And, by seeing the side through some tough times - not least in India recently when Joe Root might have endured a chastening start to his captaincy career - he absorbed much of the criticism that might otherwise have been directed at his team-mates. He saw off three coaches, two managing directors, more than a dozen opening partners and never even broke sweat. He may not always have been right, but you cannot fault Cook for his resilience or determination.

Alastair Cook racked up his 28th Test hundred Getty Images

Those strengths were, for a time, his weaknesses. The apparently unquenchable self-belief, that helped turn a relatively limited player into England's record Test run-scorer, also convinced him that he was the man to revive England's ODI fortunes. As a result he lingered too long in the role of one-day captain and was stung by the consequent criticism. While he led the team within an ace of that elusive global ODI title (the Champions Trophy of 2013) and to the top of the ODI rankings, their improvement in the format since he was sacked has been telling.

There were other significant reverses. He led the side that was whitewashed in the 2013-14 Ashes, beaten by Sri Lanka in England and held to a draw in the Caribbean by a West Indies side labelled "mediocre" by the ECB chairman. There were moments, not least at Leeds and Lord's in 2014, when he looked hapless in the field and moments, not least in press conferences and interviews, when his relative lack of eloquence prevented him from winning over the doubters as a smoother operator might have done.

There was a disconnect, too, between those who saw Cook from afar and those who saw him in action. Supporters at grounds or on tour saw a captain keen to engage and credit them for their loyalty; no selfie or autograph was turned down; sometimes he would turn to applaud the crowd from the slip cordon. But those limited to gaining their information from websites and newspapers could be forgiven for noting Giles Clarke's clumsily-stated endorsement (the toe-curling 'right sort of person' interview) or the ECB's arrogantly-worded "outside cricket" press release, and concluding that he was entitled and aloof.

He was never those things: he may have been limited as a leader and erred in judgement from time to time, but there was genuine pride and humility in his attitude. He has remained popular with spectators at games - they tend to remember and appreciate Ashes victories rather longer than the media - and there is no doubt he will receive a rousing ovation the next time he takes the field for England.

This decision is not a surprise. Cook cut a jaded figure in India and, with his performance with the bat and in the slips dipping below his own high standards, he looked as if he could well do without the burden of leadership. He may well have wanted to sign off after a successful Ashes tour, but he knows captaincy is not about personal goals and that Root requires time to settle before such a series. If the hunger for the challenge had dimmed, he had to go. Few would begrudge him a few years amassing runs at the top of the order. He's only 32; it's not impossible that the best batting of his career could be in front of him.

It would be a major surprise if Root is not named Cook's successor in the coming days. He may lack experience - Root has led in only four first-class games (and none since 2014) and only one of those matches has resulted in victory - but he has grown in stature in recent times and appears a natural leader of this young side. Assured of his place in the side, popular and respected by his peers, he may turn out to be a more natural fit for this more positive team and its coaching staff.

The only concern is the long-term effect on his form. As a key member of the side in all three formats - and a new father as well - the demands on Root are already substantial. While many new captains experience a short-term bounce in their own returns, England's never-ending tour will test him in ways that cannot be predicted. Take the winter of 2017-18, for example: those involved in all formats will leave England in October and return in April. It is a greedy, self-defeating and arguably immoral fixture list. Root needs protecting from it if he not to be burned out by 30.

Still, he enjoys a better inheritance than Cook did in 2012. Whatever England's issues - and the imminent loss of their leading fast bowler is looming - the dressing room in recent times has been as settled, supportive of one another and united in purpose as any for a long, long time. Cook has to take much of the credit for that and there is no doubt he will prove a loyal deputy to Root as required.

So, a great captain? No, few would claim that. But one who presided over some great moments in the history of English cricket? One who gave their all in sometimes desperately demanding circumstances? One who will be remembered with affection and gratitude by the vast majority of those he played with? One who did their best and met both triumph and disaster with modest good humour? Yes, all those things. It's probably unreasonable to ask for more. English cricket will look back on Cook's turbulent reign with respect, gratitude and admiration.