After a bestselling series of novels for children set in the stone age, Michelle Paver is moving to the bronze age with a new series of books, Gods and Warriors, set in ancient Greece.

As rain pounded the roof of the tent, the author told the Edinburgh International Book Festival that the Mediterranean was full of "uncertainty, because you never knew when a storm was going to flatten your crops".

The five-book series will focus on Hylas, a poor young boy who lives with his sister and who Paver said "lies and cheats and steals if he has to".

Hylas is joined by Pirra, a 12-year-old girl from Crete whom Paver described as "unimaginably rich", and who is fleeing an arranged marriage.

"I've loved this period since I was a kid," Paver explained to a packed audience, holding up two battered Puffin books about ancient Greece which she has owned since childhood. "I loved the myths of ancient Greece and Egypt."

Paver spoke about her extensive research process, which has seen her go swimming with dolphins in the Azores and climb the volcano Stromboli in Sicily. "Mostly," she said, "research is much more fun than the actual writing."

Paver's children's novels are based on historical, rather than fantasy, worlds. The last instalment of her Chronicles of Ancient Darkness series, Ghost Hunter, won the Guardian children's fiction prize in 2010.

"I want to make the world real," she told the audience. "I have to be able to believe that it could happen. I can't put Pegasus in my stories because horses can't fly. It's just a quirk in my brain."

The author was tight-lipped about future plot developments, but revealed that some of her inspiration has come from a little further east. "I've got a really exciting ending for each book and a humdinger of an ending for the last book – which I thought of in my yoga class," she said.