Rosemary Sutcliff has always been a favourite of mine. I had a steady diet of her historical novels from the time I was 12 to when I was 15. Although many of her books were written for the younger reader I still enjoy them now.
Her finest work is Sword at Sunset and that’s definitely not a childrens’ book. It raised the bar for everyone writing about King Arthur and set a pattern for other authors to follow.