The Gregorian calendar proves that Jesus existed
"Look at the date/year on our calender - 2000 years ago since what? Our historical records (other than the Bible) record evidence of Jesus' existence."
- — from 50 reasons to believe in God
"Our calendars are based on Jesus Christ. Ok. Whether you believe in him or not. Every time you sign your calendar, you write down today's date, you are saying he is here."
- — Si Robertson 
- Many (though not all) atheists concede that a religious teacher named Jesus may have lived in Palestine approximately 2,000 years ago. However, there is no historical evidence of any of his purported miracles or resurrection. Without such evidence, there is no reason to believe Jesus was a deity or supernatural being. Refer to the historicity of Jesus for more details about these disputed historical records.
- To maintain a consistent dating system, we can choose to start a new calendar at any other arbitrary agreed upon point, or we can accept a reasonably consistent and well-defined system already in place. The original arbitrary zero point of origin is irrelevant.
- The Anno Domini (AD) dating system was not created until 525 AD. It is not independent, contemporary historical confirmation of the New Testament. The current Gregorian Calendar was drafted in 1582 under the direction of Pope Gregory XIII of the Catholic church, and cannot act as evidence of the existence of a man who is thought to have lived 15 centuries earlier. This is a red herring.
- The standard calendar also involves weekday and month names that have their origins in Greek, Roman and Norse mythology. That doesn't mean that their respective gods are real as well. For example, Wednesday, Thursday and Friday are named after Odin, Thor, and Freya respectively.  Referring to these days does not mean the Norse gods actually exist!