Alastair Cook had become “drained” as England Test captain, says England’s director of cricket Andrew Strauss.
Cook stepped down after a record 59 matches in charge.
“He was getting drained by the relentlessness of being England captain,” Strauss said.
Strauss added that vice-captain Joe Root would be a strong candidate to take over but refused “to rule anyone in or out of the role”.
Cook is England’s highest run-scorer in Test cricket with 11,057, while his 140 Test appearances and 30 centuries are also national records.
But the Essex batsman had been considering his future as captain after his side suffered a 4-0 Test series defeat in India last year.
And Strauss said the 32-year-old had taken time to come to his decision.
“We know it has been a tough winter and it was an obvious time for him to step back and reflect and consider and have thoughts about what was right for the team moving forwards,” he said.
“In my conversations with him in January it became clear that Alastair felt a huge amount of energy, drive and determination was needed to drive the team forward over the next 12 months.
“You are the only one who knows how much gas you have left in the tank and how much the many demands of being England captain are taking out of you.
“He feels it is time for new blood, new impetus and fresh thinking and allow someone else to take over and do that.”
Strauss said he did not attempt to make Cook change his mind, and explained: “Once it became obvious how clear his thinking was, it was his decision to make. It would have been wrong to persuade him otherwise.”
Is the appointment of Root a foregone conclusion?
The Yorkshire batsman, who was appointed England vice-captain before the 2015 Ashes Series is seen as the favourite for the job.
But Strauss, while praising his qualities, says that there is a process to go through before Cook’s successor is announced.