William was not simply an invader. Historical accounts state that Edward the Confessor, Harold's predecessor, had sworn to make William his heir. On his deathbed, however, he reportedly commended his kingdom to Harold's care. Some sources say Edward denied ever making the promise.
William built an abbey on the site of the battle, where it still stands.

Made the English Language Stronger
By adding ed, tion, ing and perhaps s to the endings of words ... and already having what few other historic languages had ... present, past and future tense ... the most powerful language on earth was born ... French was dropped ... and English has prospered ever since.
In the Greek you can not say "once saved always saved" it is impossible. It contains ideas as to timing that simply do not exist in the Greek.