Where does “brief” come from?

brief (Middle Dutch) comes from Latin brevis, from Proto-Italic *breɣʷis, from Proto-Indo-European mréǵʰus, from Proto-Indo-European mreǵʰ- — short.

Ancestry of “brief”, step by step

Step	Language	Word	Meaning
1	Latin	brevis	short, small, little, narrow; brief, short;...
2	Proto-Italic	*breɣʷis	—
3	Proto-Indo-European	mréǵʰus	short; brief
4	Proto-Indo-European	mreǵʰ-	short