Every Zelda game has its secrets, but nothing entertains fans of Nintendo’s legendary adventure series more than discussing how each of its many chapters fit together.
Zelda is, of course, pretty much the same story every time. There’s a hero, a princess, a baddie. There’s a land to explore, bosses to defeat and useful tools just lying around mid-way through each dungeon to find. This repetition allows most Zelda games to stand alone, not needing you to know any backstory before jumping in. But fans like backstory, and they enjoy joining the dots from the minor references Nintendo sometimes does include to other games in the series.
The Legend of Zelda: Breath of the Wild is the only major game in the series not yet placed within the series’ official chronology. A Zelda timeline was published a few years back in Nintendo’s official Zelda companion book Hyrule Historia, which for the first time set down the series’ complicated history on page. But this was before the release of Breath of the Wild, and so it is not included.
Source: Eurogamer Eiji Aonuma explains why Zelda: Breath of the Wild's timeline placing must remain secret