How much do we actually know about the practices of ancient druidism in ancient Ireland, Scotland, Wales and England?

I know that the modern 'neodruidism' movement is mostly based on invented romanticism of the 19th century and fabrication in the 1960s, and not based at all on actual historic druids.

Here's what I have found in my research, but I'm not sure how much is accurate:

-they did a ritual involving mistletoe and sacrificing a cattle, mistletoe was sacred in their religion (according to one of the Roman generals, I think Julius Caesar)

-They did some kind of wickerman ceremony involving human sacrifice.

-they sometimes dug up trees and then buried them upside down, as a gateway to the otherworld.

-they had an ancient language called Ogham, but did not write any of their rituals down.

-they sacrificed people by choking them with garrote and then threw them in to bogs. The people they sacrificed seemingly went willingly.

-they took great pride in beauty and physical appearance.

-they used psychedelic mushrooms and other drugs to go in to ritual trances.

-they had some kind of belief in shapechanging.

I am writing a comic about ancient druids in Ireland c. 180-250AD and I'm trying to keep it historically accurate as I can. I read many of the ancient Irish myths and stories, but they contain alot of myth and exaggeration, as all myths do. That's why I'm asking for any info or knowledge you guys might have about them. Thank you!

It seems in watching old movies or reading about history that the sense of honor has been very important in terms of it's ability to shape the actions of individuals or cultures (people were worried about how their actions influenced their honor). I feel as though this sense is generally lost in today's society (at least in the west, I cant speak for eastern cultures). Nowadays, people dont worry about how their actions affect their honor, nor does the general population consider how honorable an individual is, at least not in such direct terms. Has the term "honor" simply become obsolete, or replaced by some similar principle? Is it too vague a notion for todays society? How has the sense of honor evolved over the last 100 years in American/western culture?

My understanding is that the Germanic tribes that conquered Europe had some kind of allegiance to the Roman Emperor, and that after the fall of the Western Roman Empire, that allegiance was transferred to the Eastern Roman Emperor. If my understanding is correct, what was the point of establishing the Holy Roman Empire? Did Charlemagne ever have an allegiance to the Eastern Roman Emperor? Was this allegiance broken after the establishment of the Holy Roman Empire?

Similarly, what authority did the Pope have to crown Charlemagne Emperor? Was he using it as an opportunity to increase his power? Was this part of the schism between the Eastern and Western churches? How did the two Roman empires see each other? Did they consider the other one "fake"?

Artist Lee Jung-seop was married to a Japanese woman, and they had children together. How was that viewed? Also, how was the rule of law during this period. Say Lee's wife wanted a devorse, would Lee be fairly treated in court?

Did cities in Central Asia compete for Silk Road merchant activity? In what ways?

Were merchants taxed at these cities?

As the title says, I've recently stumbled upon the wikipedia article about the Blitz and I was suprised to find out that Hitler was initally opposed to the idea of 'terror bombings' that would target civilian buildings, mostly because he feared what the RAF would have done in retaliation. That changed after 24 August 1940, when some Luftwaffe elements drifted off course, and the bombs they dropped killed some civilians, which triggered an immediate British retaliaton with the RAF bombing Berlin. The German response to this is what is commonly known as "The Blitz". Is this correct?

Some followup questions: if he was afraid of retaliation, why didn't he try to reach an agreement with the British government (something like "okay sorry about that, how about we don't bomb your cities, you don't bomb ours")? Did he think the Luftwaffe was winning the Battle of Britain anyway? And if yes, why fear retaliation in the first place? And how was Hitler's policy regarding bombings in other countries (eg. France, Poland)?

In general, are there noticeable facial differences between contemporary white people and their ancestors in Medieval times?

I have always wondered this, because at the time they spoke Latin, correct? Would it sound similar? Completely different? Any insight into this would be great; this has always been a blurry topic for me. Thanks!

Where are they today and who is more related to them? It is mentioned when I was reading about the Mamluks in Egypt as they are descendant from them.

The World of the Vikings by Hall seems to be more about the Viking village, which is interesting and I may read it later. However, right know I am more interesting in the whole history of Viking conquests and explorationns, especially their history in modern day Normandy, France.

Are there any surviving works from the ancient world describing how people learned foreign languages? If people learned a foreign language at that time, they most likely learned it through an immersion environment, but were there any courses or maybe some works that describe some tips? The most likely work of this type would probably come from the Ancient Romans, since many of the elites tried learning Ancient Greek.

Can someone point me to some works or maybe some current research in this area?