ひとつには…ためである => Partly because of ... N3
Cause, reason
~にしてはじめて      => since at ~ N1
ひとつ => A little N3
Repetition, habit
せめて => at least; at most ~ N2
~をこめて => filled with; full of N2
を込めて => filled with; full of N2
をめぐって => concerning; in regard to ~ N2
てはだめだ => If... then not allowed... N3
Ban
~せめてもの => at least, at most N1
Compare
て(は)はじめて => not until; only after (first time) N3
~且つ(かつ) => and N1
Line up, list
~かつて => once; before; formerly; ever; former N1
Time