Which historical figure can historians say is the most ancient individual that Humanity know of? Let's take out of the equation obvious mythological figures such as Adam or Eve, or even persons for which the reality of the actual existence is still disputed
Due to the advances in medical technology and overall worldwide food abundance and population boom over the last two centuries, the statistical probability for older and older humans has only gone up with time. This means that there are no confirmed ancient historical figures who could be claimed as the oldest. The oldest people to ever have been born, were only born in the last ~150 years. There are of course those throughout history who have claimed extreme age, but there is no proof for any of these claims. The longest living human being ever recorded was Jeanne Calment.
Sorry if this isn't what you were looking for, so to cheer you up here is the beautifully written paragraph on Calment I saved off of reddit a few months ago.
"Jeanne Calment was born in France to a shipbuilder. When she was 13 years old, she met Vincent van Gogh. When she went to the hospital to give birth to her first child, she was amazed to see the electric lights there. When she was 32 years old, she saw a car for the first time. She witnessed the invention of human flight, and made aeroplane toys for her child. Her husband was too old to fight in World War 1, but her grandson served as a medic in World War 2. She took up fencing during the 1960s, and watched the moon landing on her first TV set at the age of 94. Movies were invented when she was 20 years old, but the week she died, her nursing home was holding a screening of Independence Day. She predated light bulbs, but could have shopped on Amazon. She could have gone to a Daft Punk show and reminisced about the invention of the wax cylinder. She could have logged onto a history-themed web forum and offered her reminisces about the ongoing Jack the Ripper case. She watched her 72-year-old husband die, and then lived another 55 years."
I'll take a stab at this one.
Iry-Hor
He was probably a Pharaoh around 3200 BC, and the first Egyptian king we know by name. At least, that's the going theory, it's also possible Iry-Hor just means "property of the king"
If it isn't Iry-Hor then it's probably Sekhen, who is thought to have succeeded Iry-Hor. Sekhen, a.k.a. Ka, more than probably existed and lived ~3150 BC. Sekhen, may or may not be a pharoah named Narmer.
Narmer succeeded Sekhen (or was Sekhen) and probably, really, really, did exist around 3100 BC, but it's not entirely clear who he was, what other names he might have gone by, or what role he had in the unification of Egypt and the resulting dynasties.
There are older historical figures who probably existed in one form or another, but at this point are really just mythology.
Kayumarth of Aryans, for example, probably did exist around 5000 BC, but I doubt he invented the calender, writing, and taught the animals which food to eat, among other things.
You may be interested in the “Who is the earliest historical figure?” section of the Popular Questions pages, found in the sidebar.