Brief History of the Marque
Manufactured by Motorradwerk Matthäus Graf Thun (MT), Traiskirchen, Vienna 1925-1935 
Using engines from Villiers, JAP, Blackburne and MAG, motorcycles were built along English lines in capacities of 147cc to 497cc, along with a 750cc V-twin JAP. The Villiers engines included the famed 344cc twin and a 247cc watercooled single. It is said that some of the machines were badge-engineered Sun models.
The 1933 range consisted of 350 SV & OHV JAP models, 500cc SV & OHV JAP Models, a 750cc SV JAP V-Twin and two Villiers models, a 250 and a 350.
The firm was quite active in competition.
Count Mathias Thun was known in Paris for his involvement with the French marque La Préféré in 1914 - see French Marques (L).
Notes. 1. Also spelled Thunn - see thunweb.com
Sources: GTU Oldtimerservice, Tragatsch p222