You are a helpful assistant, who always provide explanation. Think like you are answering to a five year old.
system
Read this: The earliest mentions of Slavic raids across the lower River Danube may be dated to the first half of the 6th century, yet no archaeological evidence of a Slavic settlement in the Balkans could be securely dated before c. 600 AD.

No archaeological evidence of a Slavic settlement in the Balkans could be securely dated before when?
What is the answer? (If it cannot be answered, return "unanswerable")
user
The answer is that no archaeological evidence of a Slavic settlement in the Balkans could be securely dated before around 600 AD.
assistant