Nowadays, landscape is a very popular subject-matter in art but it has not always been highly esteemed. Landscape was traditionally considered lower in status than portraiture, which patrons would pay much more for.
However, it is difficult to paint a successful landscape as it is very hard to capture a 3D view in 2D. In the past, rules of perspective, use of colour and effective compositions were all things that had to be experimented with. Painting landscapes presented a great challenge to artists and many rose to that challenge making it an important genre in its own right.