Linda Colley

Traditionally, royal females who have not had the luck to become queens regnant have been granted very limited roles. They have been expected to look pretty, be discreet, do charitable good deeds, and - if married to princes or kings - be quietly supportive and, above all, fertile.

Since the Second World War, as female expectations and opportunities have risen, becoming a royal woman - and remaining a royal woman - has seemed less and less an attractive proposition.

Captives' was a deliberate bridging exercise, an attempt to use detailed knowledge of what Britain was like on the inside, to reach a deeper, more variegated understanding of how its peoples experienced external adventures and aggression over a quarter of a millennium in four continents.

To be sure, political unions between European countries have often failed in the past, but usually only after relatively brief periods. Denmark and Iceland separated after 130 years; the unions between Spain and Portugal and between Sweden and Norway each lasted less than a century.

In the past, Britons were scathing about the cruelties of the old Roman empire and the excesses of Catholic empire builders such as the Spanish and the French. They convinced themselves that their empire was different and benign because it rested on sea power and trade rather than on armies.

In the past, the imperialism of the West, like that of the rest, was often difficult - for the doers as well as for their victims - but western states were, nonetheless, usually able to dispatch forces overseas against non-western peoples without any fear of being attacked themselves. That kind of immunity is probably now a thing of the past.

I write to relieve an intellectual itch. I stumble across a hitherto neglected set of events, transformations, characters, or source materials from the past, and they nag at me until I make sense of them in words. But I also write to seduce and to make my readers think.

Most national holidays in most countries rest on selective memories of the past.

In the past, rulers led their troops into battle and, even in peacetime, called themselves fathers of their people. And modern politics retains abundant masculine rituals. Prime minister's question time in Britain, for instance, is a stylised duel and tournament redolent of testosterone.

Now, as in the past, rank is closely associated with modes of representation and display: with making an ordered arrangement of people or things visible and evident to onlookers in some fashion.

In the U.S. - and elsewhere - successful parties need a storyline that voters can relate to, an intelligible plot of some sort, especially now that so many older, formal ideologies have lost force. For proof of this, one has only to look at Margaret Thatcher's career and ideas.

One of the reasons why the personnel of U.S. politics are more diverse is that - unlike the U.K. - one can compete for the top job without spending long years, or any years, in the nation's legislature.