Most importantly.
In front, prominently forward.
First in time.
Positioned in front of (all) others in space, most forward.
Coming before (all) others in time.
Closest to the bow.
Of the highest rank or position; of the greatest importance; of the highest priority.
In addition; also; besides.
Next in order of place.
At that time.
At the same time; on the other hand.
Used to contradict an assertion.
In that case.
Soon afterward.
Being so at that time.
That time