So why start off with the Greek Seputagint?

So why start off with the Greek Septuagint?
Before Christianity existed as a system of worship. There were many Greek speaking Jews. Who wanted a Greek translation of the Tanakh. What we know as the Old Testament! The very fact a letter from a pagan king was delivered to the Levitical priest of that day. Asking for a translation, showed how serious the Greek speaking Jews wanted to read the Word of God. I also made it clear at least one well known Hebrew speaking Jew. Thought having translation written in any other language other than the original. Was considered heretical in the first century. God chose the Koine Greek and the Apostles as well Mark and Luke. Wrote the New Testament in the dominate language of the day. Means it was God-Breathed. Secondly, the canon list named the New Testament was argued and debated over time rather than instantly accepted as some could assume in our day. The bible many persecuted and non persecuted Christians accepted was the Septuagint. So starting off with it made sense too me. This concludes why I'm starting off the Greek Scriptures.