History lessons for big powers

"It was quite a surprise. I think it was better it happened later in life than earlier. If I had had a big success early on it would probably have been impossible to live up to," she says.

Her next major book, Nixon in China: The Week That Changed The World, was published in 2007 and looked at former US president Richard Nixon's visit to China in 1972, which paved the way to the restoration of diplomatic relations between the US and China.

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Like Peacemakers, centered on the 1919 Paris Peace Conference, it was another to focus on a set piece historic event.

"I think (through this approach) you start with something vivid and you can get to all the issues through the story," she says.

The book to some extent drew on her experience of teaching Chinese history at Ryerson, which she did without learning the language.

"I must have taught Chinese history at undergraduate level for 10 to 15 years. There was a great deal of work in English and French so I was very lucky. I learned quite a lot."

MacMillan still thinks Nixon's visit was a pivotal historic moment, not least because it was the first time an American president had ever been to China.

"It was a recognition that something fundamental had changed in the relationship between China and the United States. I think it was the symbolism of the visit that was important as opposed to the actual content," she says.

She says few of the actors at the time foresaw Deng Xiaoping's reform and opening-up of the late 1970s or that China was going to transform into a world economic superpower.

"I think neither Nixon nor (then US secretary of state Henry) Kissinger thought relations would develop as they have. There was a wonderful phrase from Kissinger when he said that he thought that trade between the two countries would not amount to much."

MacMillan, who moved to Oxford in 2007 to head St Antony's, a college for graduate students, says the problem with US-China relations is that both parties view themselves as "civilizations" and not just nation states.

"Both tend to see themselves as role models for the rest of the world. They are both convinced they are right and their way of doings thing is right. It therefore doesn't always make for an easy relationship."

She acknowledges that when China becomes a larger economy than the United States, which some predict may happen by the end of the decade, might be seen as a key historical event. "China has a population around four times bigger than the United States so the average Chinese is not nearly so well off. Technologically also the United States is still way ahead. But China is beginning to translate its economic and military strength into real power."

MacMillan says whatever happens, the Chinese will retain a deep sense of their own history.