Oxford English Dictionary: Empirical - adjective, Based on, concerned with, or verifiable by observation or experience rather than theory or pure logic.
Clearly, verification by observation or experience cannot be applied to historical characters. We can only read what others have written about them.
We are born into this world without knowledge. When we are taught, we are taught from books. Most of our knowledge comes from reading what others have written. For all historical events and characters, we are reliant upon written testimony, whether recorded in stone or upon other materials.
No one questions the existence of Buddha or Mohamed. The evidence is the religions based on them, supported by written documents.
In the case of Jesus Christ, we have the Old Testament prophecies written before he was born, and fulfilled in him. We have the written testimony of four gospel writers and five letter writers whose testimony put their lives in danger for no profit. This testimony has for the most part been carefully preserved by transcription down the ages.
We have the evidence of a Church, established, not by force of arms but by the preaching of the gospel. The preachers frequently died because men preferred to believe in the existence of idols.
As far as the scriptures are concerned we have the evidence of fulfilled prophecy in the kingdoms of men, with more to come.
The scriptures are unique in explaining the purpose of the creator, why we die, and how we can attain resurrection from the dead to eternal life. Without Christ, the scriptures have no meaning.
The written evidence is sufficient to convince me. Those who consider the scriptures to be fiction, need to find real reasons for their decision. Others must read the scriptures for themselves and make up their own minds.
I hope you find this helpful.