Fetching details from the dictionary...

long (distance, length)
long (time); protracted; prolonged
永い間お世話になった。
I've been in your care for a long time.
祖父母の結婚生活はとても永かった。
My grandparents' married life was very long.
二人の付き合いはまだそう永くない。
Their relationship is not that long yet.