Vedas are treasures of knowledge responsible for the sustenance of this universe.
WHO WROTE IT?
Its not man made. It is attained through meditation by the sages and been documented. Vyasa Maharshi has compiled the Vedam into 4 parts and hence he is called Veda Vyasa.
WHEN WAS IT KNOWN?
155.521 trillion years ago. This is scientifically proved too and this is the age of the universe. (Lets see how it is calculated in further slides)