You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Crucifixion_of_Jesus

Context:
An early non-Christian reference to the crucifixion of Jesus is likely to be Mara Bar-Serapion's letter to his son, written sometime after AD 73 but before the 3rd century AD. The letter includes no Christian themes and the author is presumed to be a pagan. The letter refers to the retributions that followed the unjust treatment of three wise men: Socrates, Pythagoras, and "the wise king" of the Jews. Some scholars see little doubt that the reference to the execution of the "king of the Jews" is about the crucifixion of Jesus, while others place less value in the letter, given the possible ambiguity in the reference.

Question:
Where can an early non-Christian reference be found to the Crucifixion?

Mara Bar-Serapion's letter to his son