オウ, い.く, いにしえ, さき.に, ゆ.く, みち
journey, travel, chase away, let go, going, before, formerly
JLPT1 G5 S8 F1421
The relevant seal inscription form is 王# (extend) + a stylized rendering of an oracle bone character combining a leg in motion + 彳 movement → make an extensive journey → *go*; *gone* → *past*. There is no etymological connection between 往 and 主.
[Full Kanji Etymology List]