Over the Sea's Edge (1971) is the latest in this long string of disappointments. It is the story of a modern boy who swaps lives with a medieval Welsh boy. Now Dave is Dewi, the boy charged with looking after his lord's pack of hounds, and gradually his modern memories fade and Dewi's reality takes over. It is a tense time for Wales, with lots of internal fighting as well as the Normans to fight, and when Prince Madauc is almost killed in Dewi's own castle's courtyard, Dewi finds himself caught up in a great adventure.
Me--time travel to medieval Wales! yes please.
Madauc has heard tales of a land far to the west, where riches are to be had, and he's determined to go there and get them to secure his own position in Wales. So a boat is built, and it reaches the Americas...
And things go down hill as far as I am concerned.
Me--oh God no. Can we just not with white people inserting romanticized white savior people where they don't belong?
The people they meet in North America are a strange amalgam of Mayan/Mississippian cultures, with a colony of earlier Welsh descendants taking center stage. And there's strange dark magic going on to add to unconvincing Native North American worldbuilding, which the Welsh contingent saves everyone from. I was, like, "gah." It was not a convincing, realistic, well-rounded picture of Native North America, it was the setting for a Welsh prince to explore. And Madauc, who at first seemed to have promise as an interesting character, gets pretty single minded about the gold thing, and Dewi stops thinking interesting thoughts about the situation as his memories of modern times vanish pretty much utterly.
And they fall in love with beautiful Native Girls, Maduac's a Mayan priestess type girl with long flowing dark hair who thought he was a god, and Dewi with a nice little Welsh descendant. "Falling in love" is perhaps the wrong term, as it implies a depth of emotion; "wanting to snog" is more accurate. The (possibly) Mayan young woman seems to have a strong character, but because of the language barrier, she doesn't get to talk till the end of the story, so basically she is simply an amalgam of long dark hair (which she unconvincingly wears loose and flowing), Native "superstition", and regalia.
I also dislike pre-Columbian North Americas that are empty enough so that Europeans can think to themselves greedy thoughts about what to do with all that empty land, because in fact North America was pretty firmly inhabited already.
I also dislike medieval Europeans who seem essentially lacking in any culture themselves. This group of travelling Welsh folk weren't believable in any cultural sense either. No thoughts about Christianity for instance. No superstitions of their own in evidence. No strong feelings of difference when confronted with other cultures.
The North American setting is a continuation of Jane Louise Curry's earlier book, The Daybreakers, which I guess I will have to read some day if I want to read every time travel book published in English for kids in the 20th century. Having read its Kirkus review, I'm not leaping at the opportunity.
What was interesting (from a Time Travel book perspective) about Over the Sea's Edge is that Dewi never goes back to being Dave, and the book ends with Dave (originally Dewi) back in our world, appreciating his good education and not remembering much about being a medieval Welshman. (At least, I think they never swapped back. I might have to re-read the end a year from now to make sure, because this time around I had run out of interest). It really rare that time travelers don't go home again, and in this case it helped the book achieve a reasonably satisfying ending (viz plot), because both boys are happier in their new times.
But really my take home message is "never read any fiction about the medieval Welsh in North America." I likewise strongly disliked Madeline L'Engle's An Acceptable Time.
Here's what Kirkus said about this one back when it first came out.