Answer: the two methods that can be used by historians when a historical record is not dated are radiocarbon dating and comparing them to other sources
Explanation: When historians use radiocarbon dating they are able to determine the age in which a particular thing occurred through objects that contain organic substances in them.
by comparing historical events to other related historical occurrences historians are able to compare the two and denote the date on which they occurred. But the exact date won't be dated since they are not so accurate.