Wondeful blending work. Not sure if the shading is needed on the left side of the painting though. Was it on the source painting.
Thanks, the painting called "Goethe in the Roman Campagna (1786)" its a Oil painting by Johann Heinrich Wilhelm Tischbein. Look here: http://cache.eb.com/eb/image.id=43663&rendTypeId=4
The integration of the cannon into your source image is handled nicely. You will, however, have to spend a bit more time on the recreated background to the left as it is quite choppy with the repeated elements clearly visible. As there was not much to work with to the left of the model in the source image, try extending a gradient fill using the existing reddish-brown colour to the left of your image and sweeping upwards to the lighter colour by the structure in the background (centre). Apply a bit of noise and texture if necessary to match the existing strokes. I would remove the lighting effect from the left so as to eliminate the shadow halo on the left side of your work and also to reduce the contrast level of the man in the source image. A final touch would be to make the top-right of the wheel in the foreground just a bit darker where it comes in contact with the man as well as darkening the face of the gun carriage underneath the man.