We've talked about the Aryans being the original farmers - and that the term 'Ar' is both the root of 'Arya' (Aryan) and 'arable' (land to plough). Many Indo-European words meaning 'to plough' are the same as 'Aryan', for example the Old English 'Erian' and Gothic 'Arjan'.
Our Germanic ancestors pictured the constellation Ursa Major as a plough. The Viking Norse word for plough was 'arþr' (Arthur) which is probably how the christian distortion of the name to 'Arthurs Wain' (as in King Arthur) came about. Other Germanic names for Ursa Major included 'Churle's wain' (mens wagon - with Ursa Minor being 'Lady's wain) - again christians corrupted the name so it became 'Charles Wain' after Charlemagne.
Whilst today the symbol is used by Irish republicans and leftist's it shouldn't be forgotten that the term Eire (Ireland) itself means 'Ara' (Eirean = Aryan).