... or has the value of currency gone down?

It is an interesting way of looking at things - something that was being dicussed on Russia Today at some point a few days or weeks ago.

Generally, we are told that the value of Gold has doubled or so over a period of time.

Another way of looking at the same information is that you now need twice as much currency to buy the same amount of gold.

So has the value of gold gone up or has the value of currency gone down without us even noticing?

There was speculation about "currency wars" recently where countries may lower the value of their currency to gain "unfair advantage" by improving their exports... how do we know that this has not already been happening? If every currency is devaluing itself when compared to others, the relative values of the currencies could stay the same, but the price of good increase... which has happened to an extent (but generally not that large of one).

So what is really happening?