Our house was guarded by three mongrel dogs. Sly was a huge black Rottweiler pup, big paws and playful, yet fearsome because of his size. Sly was a harmless sook who slept on Simon’s bed. Then there was Darius, a muscular mix of bull terrier and Rhodesian ridgeback. Darius was rusty brown and huge, like a canine wombat. He was both untrainable and unkillable.