sorry, dont know what went wrong. ill try again but less fancy. https://www.history.com/topics/halloween/history-of-halloween#:~:text=The%20tradition%20originated%20with%20the,of%20the%20traditions%20of%20Samhain.

and another incase that didnt work:
https://www.britannica.com/topic/Halloween

im no expert, i was just curious by what you said so looked it up. im doing so, i assumed that what you said about the romans having halloween in 600ish was true, and so when i read about Samhain and it coming before that, i reckoned the romans must have been influenced by the celts rather than the other way around, since Samhain does sound awfully halloweeny, what with the dressing up to ward off/fool spirits and the portals to the spirit world and such, (im scottish and was taught the last part as a child, i have no idea if that idea extends to america and elsewhere) whereas the roman festivals around the same time sound far less halloweeny.

Actually, it appears the Romans were influenced by celts.

>By 43 A.D., the Roman Empire had conquered the majority of Celtic territory. In the course of the 400 years that they ruled the Celtic lands, two festivals of Roman origin were combined with the traditional Celtic celebration of Samhain