Preliminary to this design, a careful research was done on the proportional theory of Dom Hans van der Laan. Based on how we perceive space and measure things this system offers a way to create harmonious architecture. What can we learn from this theory for today's architecture and what is the relevance? Starting from the ideas of Dom Hans van der Laan concerning proportion and perception, this design for a modern monastery in Rotterdam is a statement towards our mental health and the importance of careful design in relation to that.