The 149th Open Championship has been cancelled but 2020's three other men's majors have been rescheduled because of the global coronavirus pandemic.
The Masters has been put back from April to November, while the US PGA Championship is slated for August.
The US Open, at Winged Foot, New York, is being moved from June to September, a week before the Ryder Cup.
The Open, due to take place in July at Royal St George's in Kent, will now be hosted by the venue in 2021.
R&A chief executive Martin Slumbers said: "We have explored every option for playing The Open this year but it is not going to be possible."
However, all three of the majors hosted on American soil each year are still hoping to go ahead. And the Ryder Cup - the biannual event that pitches Europe's finest golfers against their American counterparts - is being kept in its late September slot.
Major dates for 2020
- Cancelled: The Open Championship
- 6-9 August: US PGA Championship, TPC Harding Park, San Francisco, California
- 17-20 September: US Open, Winged Foot Golf Club, New York
- 25-27 September: Ryder Cup, Whistling Straits, Wisconsin
- 9-15 November: Masters, Augusta National Golf Club, Georgia
The PGA Tour's season-ending FedExCup Play-offs are scheduled to take place on four successive weekends from 13 August.
'Open decision made with a heavy heart'
It is the first time The Open has been cancelled since the 1940-45 tournaments were not played because of World War Two.
The 149th Open will now be played at Royal St George's in Sandwich from 11-18 July 2021, meaning the R&A can keep the 150th Open at St Andrews in Scotland, from 10-17 July 2022.
In a statement on the R&A website, Slumbers added: "We care deeply about this historic Championship and have made this decision with a heavy heart.
"We appreciate that this will be disappointing for a great many people around the world but we have to act responsibly during this pandemic and it is the right thing to do.
"We rely on the support of the emergency services, local authorities and a range of other organisations to stage the Championship and it would be unreasonable to place any additional demands on them when they have far more urgent priorities to deal with."
Ireland's Shane Lowry, who won last year's Open Championship at Royal Portrush in Northern Ireland, tweeted: "Obviously I'm disappointed that I won't get to defend the Open Championship this year but I feel the R&A have made the right decisions based on people's health and safety. See you all in Royal St George's in 2021."
The R&A said all tickets bought for this year's tournament will be transferred to next year's event, with full refunds for those people who are no longer able to attend.
Royal St George's has hosted The Open 14 times, most recently in 2011, when Northern Ireland's Darren Clarke won for the first time.
The Open, which started in 1860, was also previously not held from 1915 to 1919 because of World War One.
The only other previous cancellation came in 1871, when no trophy was available because Tom Morris Jr was allowed to keep the Challenge Belt for winning the tournament three times in a row.
The Claret Jug, the prize for the champion golfer of the year, was introduced in 1872.
BBC golf correspondent Iain Carter
A golfing year without The Open is hard to imagine.
Outside war years it has only happened once before and that was in 1871, long before the championship had become such a huge global event.
Staging the 149th championship in the current situation was always going to be a tall order. Work to erect the temporary infrastructure to house about 200,000 spectators during Open week is a massive undertaking.
Any plan to stage it without fans would have been costly given that the event is now pre-paid and only a few tickets were left unsold.
By delaying a year and pushing St Andrews back to 2022, the 150th Open will still be played at the venue known as the home of golf.