What this map means is that it’s the local version of the name. Every name on this map evolved gradually from the Hebrew יוֹחָנָן (Yochanan). The Greeks turned it into Ioannis, then the Romans got it from them and turned it into Iohannes, then in England it became Johannes, and then over time in England it became Johan and then John. Meanwhile, over in Russia, they went from Hebrew Yochanan > Greek Ioannis > Russian Ioanna > Russian Ivan. They sound different now, but they are both “the name of those two important guys in the bible”
What this map means is that it’s the local version of the name. Every name on this map evolved gradually from the Hebrew יוֹחָנָן (Yochanan). The Greeks turned it into Ioannis, then the Romans got it from them and turned it into Iohannes, then in England it became Johannes, and then over time in England it became Johan and then John. Meanwhile, over in Russia, they went from Hebrew Yochanan > Greek Ioannis > Russian Ioanna > Russian Ivan. They sound different now, but they are both “the name of those two important guys in the bible”