All calendars start at year 1 on the same day, and there’s no way to define a correspondence between them. So year 1 of every calendar correspond to every others' year 1. In practice, when working with multiple calendars (e.g., Gregorian, Persian, or a custom fantasy calendar), you need to be able to say: “Day X, Year Y of Calendar A corresponds to Day Z, Year W of Calendar B.” This would allow: Proper alignment of historical events across different cultures. Worldbuilding scenarios where different peoples measure time differently but still share a reference point. More accurate conversion when using real-world inspired calendars. Without anchor dates, every calendar is “floating” with respect to the others, which makes multi-calendar timelines very hard to manage. Thanks Braden for your hard works ! Really love LegendKeeper so far it is an amazing tool!