There's been a lot of speculation about the meaning of these lyrics. I know the inspiration for the song is a painting by Mexican artists Frida Kahlo.

I used to rule the world
Seas would rise when I gave the word
Now in the morning I sleep alone
Sweep the streets I used to own

I used to roll the dice
Feel the fear in my enemies eyes
Listen as the crowd would sing:
"Now the old king is dead, long live the king!"

One minute I held the key
Next the walls were closed on me
And I discovered that my castles stand
Upon pillars of salt, and pillars of sand

I hear Jerusalem bells a ringing
Roman cavalry choirs are singing
Be my mirror, my sword, my shield
My missionaries in a foreign field
For some reason I can't explain
Once you go there was never, never an honest word
That was when I ruled the world

It was the wicked and wild wind
Blew down the doors to let me in
Shattered windows and the sound of drums
People couldn't believe what I'd become

Revolutionaries wait
For my head on a silver plate
Just a puppet on a lonely string (Ooooh)
Ah, who would ever want to be king?

I hear Jerusalem bells a ringing
Roman cavalry choirs are singing
Be my mirror, my sword, and shield
My missionaries in a foreign field
For some reason I can't explain
I know Saint Peter won't call my name
Never an honest word
But that was when I ruled the world

Ooooh Ooooh Ooooh Ooooh Ooooh
(repeat with chorus)

I hear Jerusalem bells a ringing
Roman cavalry choirs are singing
Be my mirror, my sword, my shield
My missionaries in a foreign field
For some reason I can't explain
I know Saint Peter won't call my name
Never an honest word
But that was when I ruled the world
Oooooooh Oooooooh Oooooooh

Coldplay "Viva la Vida"

I guess the words could apply to any powerful entity's fall from grace. Some believe it is about the French revolution or about Louis XVI.
I don't really know what these lyrics are about but all I can think about is G.W. or Cheney sitting on his porch sometime in the future thinking these very same thoughts.

Yeah, I tend to agree, but it's in the air really, lots of bands/singers have been going on about this sort of thing for generations.

I have an absolute disdain for coldplay, it's just neo-liberal posturing.

bestness

I am really enjoying the new Coldplay CD. The lyrics to the title track are quite telling- agreed 100 percent. The lyrics on this album have an interesting taste to it, but then again all their songs have been very well written and composed.

On a non-political note 'lovers in Japan' is my favorite song from 'Viva La Vida or Death and All His Friends'. Chris Martin and Co. always have something to say about politics and society. Great music...

The song Viva la Vida (IMO), reflects the revolution against King Charles X that accomplished rather little other than bring in a new king to power, Louis-Philippe.

The artwork for Viva la Vida or Death and all his Friends is taken from the French Impressionist Ferdinand Victor Eugène Delacroix and is entitled “Liberty Leading the People” circa 1830. The painting was purchased by the French Government of the time yet was not displayed until the final Revolution (1848) that dethroned King Louis-Philippe and placed the newly elected President, Louis Napoleon into power.
mycoldplay.com by corinthian1858

Yet another interpretation.
I guess these lyrics apply to any head of state abusing his/her power.

Just to elaborate on the inspiration of the album cover.
According to the band the title Viva la Vida takes its name from a painting by Frida Kahlo, the acclaimed 20th century Mexican artist and active communist sympathizer who befriended Leon Trotsky as he sought political sanctuary from Joseph Stalin’s regime in the Soviet Union.

And there's this interpretation:

While you could force the song to fit any of these themes, I believe ITS INTENT was to be written from the perspective of Tony Blaire. That would be most fitting with regards to Chris' vocal objection to Blair and the War in Iraq.

For instance:
Puppet on a string - with reference to how Blair would respond to Bush

my head on a plate, and other lines about the fall of a king - with reference to how people wanted him out of office.

lines about not telling the truth - Blaire was well known for being able to spin media

reference to Crusades - allegory to spreading freedom in the middle east

St. Peter still not calling his name - maybe something is still on his conscious even after his conversion.

Hmm, and here I was thinking this song reflected the zeitgeist of the moment; how so many "masters of the universe" (big hedge fund traders and investment bankers) have seen their lives, their careers and their wealth collapse around them. "I used to roll the dice" is a pretty good analogy for speculating on stocks and bonds. "Sweep the streets I used to own" Wall Street?

"A wicked and wild wind" well, that certainly is a good metaphor for the financial storm ripping through the markets. Look, I don't wish to put words in Chris Martin's mind - it probably was all about Charles X, Napoleon or Louis XVI. All I know is there is a lot of people out there listening to those lyrics right now and thinking "that's me"!

I have listened to this song several times and find it captivating. It evokes a lot of historical imagery and yet is not time-specific. In other words- it is about any leader (king, chancellor, prime minister, president, dictator) who uses power, abuses it, is undone by it, and in the end reflects on the waste of it (sending armies off to conquer to no decent purpose). Saint Peter will not be calling any of them into Heaven; that can be the ex-ruler's reflection on their tyranny or even history's deserved harsh judgement of them.