Historical Sources for Jesus
Nobody knows whether anybody wrote anything about Jesus during his lifetime. If they did, we don't have it anymore. Jesus probably was crucified about 30 AD. The oldest piece of writing that mentions Jesus that isn't the Bible is Josephus' History of the Jews. Josephus was born about 38 AD, so probably after the Crucifixion. He published his History in 93 AD, by which time everybody who could have personally known Jesus was dead. (It's also not clear whether some of the lines about Jesus may have been stuck into Josephus hundreds of years later, not actually written by him or at that time).
The Roman historian Tacitus wrote about Jesus in his Annals, published about 116 AD. Tacitus mentions Christians having been persecuted in Rome in 64 AD, but that's not the same as a source about Jesus himself, and it's a reference to something that happened a generation after the Crucifixion.
The Roman historian Suetonius, writing about 120 AD, mentions Jews who followed "Chrestus" in Rome about 50 AD, but again the events are twenty years after the Crucifixion, and Suetonius is writing almost a hundred years after the Crucifixion.
We do have independent knowledge of some other people mentioned in the Bible. We know from inscriptions and gravestones that Pontius Pilate and Caiaphas were real people, and there are written source that tell us about King Herod.