Does Yone's ability trigger when conquering a battlefield via Skyfall of Areion (which involves holding before the battlefield is open)?

Ruling: Yone's ability does not trigger when holding a battlefield that is not yet open. Holding requires control of the battlefield, which cannot occur while the battlefield is still closed/uncontrolled.

Nuances:

• If you replace "conquer" with "hold" in Yone's ability text, it would read "When I hold an open battlefield" which is impossible since you cannot hold an uncontrolled/closed battlefield
• Attack and defender designations/abilities do not trigger when going to an open battlefield