Going north, obtained a historical garment (4)
I believe the answer is:
toga
'historical garment' is the definition.
'toga' can be an answer for 'garment' (toga is a kind of garment). I'm not certain of the 'historical' bit.
'going north obtained a' is the wordplay.
'going north' shows that the letters should be reversed in order.
'obtained' becomes 'got' ('get' can be a synonym of 'obtain').
'got' backwards is 'tog'.
'tog'+'a'='TOGA'
Can you help me to learn more?
(Other definitions for toga that I've seen before include "Old-style dress" , "This ancient robe might get your goat" , "Robe for an ancient Roman" , "Got a robe for an old Roman" , "Outer garment" .)