Who invent candle?

Impossible to be specific. The candle was a slow and painful evolution from an observation by primitive man that the fat of animals would burn if a flame were touched to it. Originally, this was a vessel with a rough fiber wick in it. It would have smoked like crazy and smelled awful, but it was probably still a miracle to our ancestors: A light after dark! And you can control it! Over many centuries, candle making developed from that. Candles were common in Europe by AD 500.