Who Created The First Encyclopaedia?

The first attempt by a single person at combining the sum of all knowledge into one great work was made by Speusippus, an Athenian, around 350BC.

He succeeded the great philosopher Plato, also his uncle, as director of the Academy at Athens. He then took on the immense task as an aid to his teaching. Undoubtedly he leant on the work of other famous philosophers and scientists, people like Aristotle.

Sadly Speusippus's work is lost to us. We do however have parts of a Chinese attempt called Erh Ya. This was something of a collaboration over an extended period in the fourth to second centuries BC. The core of the work existed in the sixth century BC and was still being added to in the first century BC.
According to the biography of its sponsor, the greatest work of that kind was Master Lu's Spring and Autumn Annals which were completed by 239 BC.