Illiterate men.

[FallentoReason]

Because, As I said Mark's work was not penned down till after the death of Peter.(70 AD)

Please state your source because all I have read point to his death being anywhere from 64-68AD by execution of the Emperor Nero.

I don't see how it could have been 70AD because Nero suicided in 68AD.

Luke's work was written much earlier for a very different reason. We know this because Luke was mentioned in Collossians, 2 Timothy, and Philemon which were all written in the life time of Peter.( died around 70 AD) and Paul(who was acredited to writting those three books died in 67 AD)

Remeber Luke's Letters (The book of Luke and the Book of Acts) were written to his, at the time, Master (Theopolus.) Luke's efforts in the other three books written by Paul were after Luke had been released from the service of Theolopus, and was now acting as an understudy to Paul himself. (Well before 67 AD)

Because I believe that your date for Peter's death is implausible, let's take the worst case scenario (in your eyes) and say he died in 64AD. This gives a 3 year gap where Luke could have written his Gospel and then joined forces with Paul after Mark had been penned down (according to your theory of when Mark was penned down). This would perfectly explain Luke 1:1-4:

[1]Inasmuch as many have undertaken to compile a narrative of the things that have been accomplished among us
-Implicitly saying that Mark was written already.

[2]just as those who from the beginning were eyewitnesses and ministers of the word have delivered them to us
-Explicitly saying that these writings have been passed around.

[3]it seemed good to me also, having followed all things closely for some time past, to write and orderly account for you, most excellent Theophilus
-Explicitly saying he is writing his own Gospel like others have.

[4]that you may have certainty concerning the things you have been taught
-Not sure what he means here. Possible saying he will confirm the content of the Gospel of Mark(?)