What does Luke 3:1 mean?

It was the fifteenth year of Tiberius Caesar’s rule. Pontius Pilate was governor of Judea, Herod was in charge of Galilee, his brother Philip ran the region of Iturea and Trachonitis, and Lysanias was over Abilene. Luke 3:1 - Modern Text Bible

(This verse sets the historical scene, naming the political leaders in power when these events happened. It grounds the story in real time and place.)