What does Michael Wood mean when he says "It was a rejection ... of a whole way of understanding history"?

I'm a fan of historian Michael Wood! One of my favorite items from him was the BBC documentary series, "In the Footsteps of Alexander the Great."

The quote you mention from Wood comes from his historical researches regarding India. (You could also look for his BBC documentary series, "The Story of India.") The "rejection of a whole way of understanding history" was the way that Wood described the actions of Asoka (or Ashoka - - you'll see both spellings). Asoka was ruler from 268 to 232 BC of lands that would later become known as India. Asoka was a great conqueror but also someone who found enlightenment through Buddhism. After conquering the Kalinga region in eastern India, rather than feeling some great rush of pride or accomplishment because of their victory, Asoka felt guilty. So he worked hard to improve the lives of the Kalinga people that he had conquered. This was what Wood was referring to when he said Asoka's attitude/approach "was a rejection of a whole way of understanding history." Conquest was not something to be celebrated triumphantly. Rather, the conquerors had an obligation to those whom they had conquered.