Tiberius was the second emperor of Rome, succeeding Caesar Augustus, the first Roman emperor. During his reign, John the Baptist was active, and Tiberius remained emperor when Jesus was crucified.
Luke 3:1In the fifteenth year of the reign of Tiberius Caesar, when Pontius Pilate was governor of Judea, and Herod was tetrarch of Galilee, and his brother Philip) was tetrarch of Ituraea and Trachonitis, and Lysanias was tetrarch of Abilene,
Therefore, the "Caesar" mentioned in Jesus' public ministry refers to Tiberius.
Matthew 22:17Tell us, then, what you think. Is it lawful to pay taxes to Caesar, or not?”
Luke 20:22Is it lawful for us to pay taxes to Caesar, or not?”Luke 20:23But he perceived their craftiness, and said to them,Luke 20:24“Show me a denarius. Whose likeness and inscription does it have?” They said, “Caesar’s.”Luke 20:25He said to them, “Therefore render to Caesar the things that are Caesar’s, and to God the things that are God’s.”
John 19:12From then on Pilate sought to release him, but the Jews cried out, “If you release this man, you are not Caesar’s friend. Everyone who makes himself a king opposes Caesar.”