'The old man shook his head cunningly. "Na--Na--Na!" he cried. "I know better. Every time I tell my tale men stone me. But, Thanes, I will tell you a greater thing. Listen!" He told us how many paces it was from some Saxon Saint's shrine to another shrine, and how many more back to the Abbey of the Battle.
'"Ay," said he. "I have trodden it too often to be out even ten paces. I move very swiftly. Harold of Norway knows that, and so does Tostig my brother. They lie at ease at Stamford Bridge, and from Stamford Bridge to the Battle Abbey it is--" he muttered over many numbers and forgot us.
This is from "The Tree of Justice" in "Rewars and Fairies" by Kipling.
I do not understand the meaning below.
I am glad if somebody kindly teach me.
I have trodden it too often to be out even ten paces.