THE DELIVERER/GABRIELLE'S HOPE EPISODE OBSERVATIONS
In the episode The Deliverer, they're in Britannia (ancient England during the Roman occupation) because Xena is going after Julius Caesar to help out Boudica her friend... and I get that they try to be at least a little bit historically accurate. They have Boudica who was an actual female tribal leader of Celts during the Roman invasion of England. However I'm not sure if Boudica lived at the same time as Julius Caesar. Would Julius Caesar have known about Boudicaor have armed his men for an attack on the part of Britannia where Boudica lived. Boudica died around 61 AD. Did these two even live in the same time period?
Who is Dahak supposed to be? He can't be Satan/The Devil since Lucifer/Satan appears in a later episode, other season (I think it's season 5 or 6). How does Dahak figure into the Celtic/pre Christian pantheon? At the end of that episode after the temple of Dahak blows up and Xena saves Gabrielle (who has been impregnated by Dahak at the altar) the ruins of the temple form Stone Henge. Is this the writers of the show's way of suggesting that Stone Henge in England in the context of the Xena universe - was Dahak's temple?
Lastly, in the subsequent episode Gabrielle's Hope, Gabby and Xena and Gabby's baby Hope are clearly in the time of King Arthur of the Arthurian legends. A group of men that serve as a prototype for the Knights of the Round Table explain to Gabrielle and Xena that they are awaiting the coming of a king who will unite their lands and save them (presumably from their enemy the Romans after pulling a sword from a stone. This is the actual source of the legends behind King Arthur. They don't mention Arthur but they do have the sword in the stone and Xena even pulls ito ut for a brief second before putting it back in it's place. So you have Boudica/Stone Henge and King Arthur in the same time period all during Xena's visit to Britannia. It's really messing with actual history and it's not a bad thing but it's a little crazy if you think about it. They also never returned to the King Arthur plot line had they followed what happened after Xena left Britannia.