Old English isn’t so much an older version of English as a completely different language. It was much more completely Germanic than modern English is completely anything. Nobody knows quite how old it is, but it died out over a thousand years ago. Although it’s one of the main sources of modern English, it operates in some ways that are completely unfamiliar to English speakers today.
One Old English word you might see used in historical fiction, and even sometimes in fantasy stories trying to evoke a medieval atmosphere, is “yclept.” It means “named” or “called.” It looks strange today because beginning a word with “y-c-l” is just something that’s not done any more.
In Old English, though, they had spelling rules that we don’t really grasp. “Yclept” reads that way because of one of those rules. “Yclept” is a form of “clepe”, which meant “to call.” Where we would say “called,” an Old English speaker would say “yclept” (ycalled). Other verbs worked the same way; you would add a “y” to the beginning, and the effect was the same as adding “ed” — or sometimes “ing” — to the end today. Technically speaking that’s forming a past participle, but never mind. “Yclense” and “ypunch” are “sort-of” examples; they’re not exactly Old English but they’re close, and they use that old rule.
On the other hand, if this was a common thing in Old English, why have we heard of this one, but not any other “y-“ words from a couple millennia ago? The answer is a man yclept “Gavin Douglas.” he was a translator and “makar” in Scotland in the late 1400s and early 1500s. A “makar” is a Scottish poet. His work is still fairly well known by people who follow Scottish poetic history; he was one of a group called “the makars” who worked during the “northern Renaissance” which was like, y’know, “the” Renaissance, except it happened in the northern part of Europe including Germany, England, Scotland, Poland, and so forth.
Anyway, during Douglas’ time, “yclept” was already ancient and had been obsolete for centuries. But he dredged it up from somewhere and used it in some of his works. He was well known and his work popular enough that he actually managed to bring “yclept” back, where it’s been used sporadically — mostly for effect — ever since. He didn’t revive any similar words though, or the rule, or else we might be talking about that time Gavin Douglas yrevive Old English.