Almost certainly by the well-known Ariston Company (who made a vast range of lathes) this interesting lathe was behind in a German army service truck in the Kongsberg area of Norway at the end of World War 2; backgeared and screwcutting, it has survived in remarkable fine mechanical condition. With a centre height of around 125 mm and a capacity between centres of 650 mm, it was stamped on the bed with a Waffen number and swastika - so confirming its likely date of manufacture as being between 1937 and 1944. For its era, this was a reasonable compact machine with a built-on, 2-speed gearbox behind the headstock acting as a countershaft - the drive to the box coming via a wide flat belt from part of the truck's drive system (though what other machinery it contained is not known).
Of remarkably robust proportions for lathe's capacity, the headstock was fitted with plain bearings and 3-step cone pulley for drive by a wide flat belt.
Drive to the screwcutting and feeds gearbox came through changwheels and a tumble-reverse mechanism - the operating lever for this being of typical German (and especially Ehrlich). Although the gearbox was a proper tumbler type, from its appearance (similar to that on other Ariston lathes) the threading range would have been limited - though both a screwcutting leadscrew and power shaft were fitted, the latter driving, though the usual worm-and-wheel arrangement in the apron, to give power sliding and surfacing feeds. A pull-push button on the face of the apron selected the feed direction with a lever on the gearbox to engage and disengage it. 
Of ordinary design, the compound slide rest had a cross slide of the short type (that would lead, eventually, to wear in the middle part of the way on which it ran) and a top slide whose stout appearance gives a clue as to the maker - being a typically Ariston design
The bed, with a wide detachable gap piece, was rather unusual in using four sets of V-ways, two for the saddle and two more for the tailstock.