The Wihtwara Dynasty by Jan Harper Whale
This is the third and final historical novel in a trilogy dedicated to the ancestors of Wihtland, Isle of Wight, who lived in peace and cared for their Island home in a sacred manner.
The journey continues for Eyvindr Wahl as he confronts for the first time, the inexorable growth of the Roman Catholic one-god religion that threatens their Pagan gods and goddesses. The power to protect them is held within the Halig Stan, the Sacred Stone. Visions tell them of missionaries sent to destroy their age-gold beliefs. Recant or die.
The nature lovers meet the weapon they use: The Word. The Word is the Lord and the Lord is Word. That weapon is Tongue Science. (Tongue Scinende) Rhetoric And when the words do not work, out come the swords, The massacre of Wihtwara in 686 C.E draws ever closer.