It's 3 AM in central London - dark and quiet except for the odd car and the hum of generators huddled round the outside of Westminster Cathedral. But here, inside, light is flooding in through the windows as though it was midday. And in the minds of the 150 or so people here it is midday and this isn't London, it's the Escorial Palace in Spain in the year 1588. King Philip II of Spain, the most powerful man in the world, is about to tell his ministers that he now has the right to invade England - the Spanish Armada is about to be launched.

But this isn't a dream, it's a movie and as the historical researcher on this and Elizabeth before it, it's a paradox I'm getting used to. People often ask me if the films I work on are 'true' - if they are 'what really happened' so on this blog I'm hoping to explain over the next few weeks of shooting a little of how history and drama are blended to make this movie, how 'Golden Age' is not simply about making a documentary but interpreting the past through dialogue and metaphor something we can all do and the thing that makes history matter to every generation.

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