The dated and signed painting, Herd in a Ruin exemplifies a new concept of space in Roos’s works. In the early 1670s it was based on the unity of composition, or else the mutual relatednesss of the various planes. A new connecting feature was seen in the path or road passing both the planes. The scene is framed by an architectural ruin - the remains of a vault form an imaginary gate. This particular form of architecture was probably inspired by depictions of the Colosseum in Rome The action taking place in the background is as important as the scene in the foreground. The clear-cut delineation of the various planes is thus suppressed. The unifying feature is the light, which illuminates the shepherdess with the herd in the very centre of the painting. Likewise, light also falls on the architectural ruins at the very back, while the shepherd in the foreground is overshadowed. In this respect, Roos followed the works of the Dutch landscape painters Nicolaes Pietersz. Berchem, Jan Hackaert, Jan Dirksz. Both or Adriaen van de Velde. He most probably got acquainted with their production through prints sold at Frankfurt art markets.