Triumph in India 2012-13
Even if Alastair Cook had remained in his role to the very end of his record-breaking career, he surely could never have replicated the extraordinary standards that he set on his first campaign as England's full-time Test captain. It wasn't simply the runs he scored (562 in four matches, including three big hundreds), it was the iron will that he demonstrated - first in defeat at Ahmedabad, and then, with unyielding resolve, in back-to-back victories at Mumbai and Kolkata - to transform the ambitions of a team that had finished the 2012 home summer with bitter divisions in their ranks. His role in the reintegration of Kevin Pietersen, post "Textgate", was integral to England's success (the honeymoon wouldn't last for long…), as too were the skills of England's spinners, Graeme Swann and Monty Panesar. But Cook's indomitable plodding, propping forward for hour after hour to break India's will in their own backyard, was the story of a stunning winter.
Ashes retained 2013
Not for the last time, Cook's personal returns in a home Ashes series were fallow - 277 runs in five Tests - but there could be no disguising his relief and pride at the end of the fifth Test, when he lifted the urn in front of the Oval crowd to confirm England's retention of the sport's oldest prize for the third series running. It was a curious series that hindsight would judge with caveats aplenty - England's 3-0 win looked extremely comfortable from a distance, but they required heroic bowling from James Anderson at Trent Bridge and Stuart Broad at Durham, not to mention rain at Old Trafford, to repel an Australian side that had started the summer in utter disarray following the last-minute sacking of their coach, Mickey Arthur. Nevertheless, as Cook boarded the plane for the return series in Australia, his captaincy record was undeniably impressive: P16, W9, L1.
Australia's revenge 2013-14
The good times were not, it seemed, built to last - and the ferocity of Australia's reclaiming of the Ashes left lacerations in England's team ethic that, in certain notable cases, would never fully heal. Mitchell Johnson's brutal pace was the absolute difference between the sides, though Cook himself was no less traumatised by the supreme skills of Ryan Harris, who could have been one of the great new-ball bowlers had he been blessed with a less fallible body. Throw in the vicious counter-attacking hitting of David Warner, and there was not a single facet of the series in which England were not left bloodied and beaten by the end of a sorry campaign. Champions of their world-beating 2011 team were scattered across the continent - Jonathan Trott at Brisbane, Swann at Perth, and of course, Pietersen, whose fate was apparently sealed during a fateful team meeting at Melbourne.
The captain's nadir 2014
Cook has never been more embattled than he was throughout his annus horriblis of 2014 - a year which started amid the fallout of Pietersen's sacking by the ECB, and finished with the captain himself being binned from the limited-overs side, only months before the 2015 World Cup, after the selectors finally twigged that strength of will alone could not atone for his lack of white-ball impetus. In between whiles, England did beat India 3-1 in the summer's marquee Test series, but not before enduring two of the toughest defeats of Cook's career - first at Headingley, where Sri Lanka swiped a stunning 1-0 series win off the penultimate ball of the contest, and then in the second Test against India at Lord's, where Ishant Sharma capitalised on a series of hook-happy batsmen to deliver a 95-run win. Had it not been for the support of his wife, Alice, Cook later admitted that he could well have jacked it all in there and then.
Ashes redemption 2015
Though he did not appreciate it at the time, the ending of Cook's flirtation with one-day cricket was the catalyst he needed to rediscover his finest crease-occupying Test form, and having finally ended a two-year wait for his 26th Test hundred at Bridgetown in May, he followed up with a masterful 162 at Lord's in a victory for the ages over New Zealand. All of which allowed him to approach the rematch with Australia in something approaching his most settled frame of mind, and by the summer's end, he had become only the third England captain, after WG Grace and Mike Brearley, to win two home Ashes campaigns. Once again, it was a peculiar triumph, featuring two crushing defeats at Lord's and The Oval, either side of Stuart Broad's 8 for 15 and all that at Trent Bridge, but, after the horrors of the recent past, England weren't complaining.
South Africa conquered 2015-16
Longevity can be a curse for Test captains - just compare and contrast, say, Ricky Ponting, whose world-beating achievements were overshadowed by three losing Ashes campaigns, and Mike Gatting, who will forever be lauded for England's 2-1 Ashes win in Australia in 1986-87, in spite of the fact that he never won again in 21 further attempts. For that reason, it is easy to overlook the significance of Cook's second most famous overseas win, in South Africa in 2015-16. Once again, his own returns were modest, but the ebullience of the men around him - younger batsmen such as Ben Stokes and Jonny Bairstow at Cape Town, and Joe Root at Johannesburg, and the old hand Stuart Broad in both victories at Durban and the Wanderers - was a testament to the elder-statesman solidity that he was beginning to bring to his leadership. Despite a reality check in the dead-rubber defeat at Centurion, England's 2-1 win was only their second in South Africa since readmission.
Out of steam in India 2016-17
England were by no means blind to the challenge that faced them in the subcontinent this winter, but if there were grounds for optimism, then they resided in the indomitably wide blade of the captain himself, whose record in Asia is second to none among visiting batsmen. He had reaffirmed his love of the long haul by racking up a massive 263 in Abu Dhabi the previous winter, and threatened a repeat of his 2012-13 heroics with a determined second-innings 130 to give England the upper hand at Rajkot, but thereafter he visibly ran out of steam as India's spinners, not least Ravindra Jadeja, probed his pads and disrupted his resolve. Without ever looking entirely out of form, Cook looked strangely devoid of hunger with the bat, and palpably lacking for answers in the field as England's spinners were shown to be out of their depth. Few leaders could have bettered a 4-0 loss with the tools at England's disposal, but Cook at his most bloody-minded might conceivably have been one of them. The time for a change was clearly nigh.