As all mysticism, Christian mysticism can only be known as far as it is uttered in language. These testimonies describe mystical experience as a direct and passive experience of God. In itself it is suprarational and above all that language can find out. Therefore its description can only proceed by negation: what is experienced is nothing of all that a human can conceive of. Still, some fundamental symbols as light, fire, water and space may suggest what mystical union is like. It strains language to the utmost and brings it to the highest form of poetic expression.
The Low Countries have known an influential tradition of mysticism. The most famous representatives from this tradition - Jan van Ruusbroec, Hadewijch, Beatrijs van Nazareth and Marguerite Porete - and their attempts to put their experiences into words have been studied extensively at the Ruusbroec Institute since its foundation. Also lesser known mystics and anonymous mystical texts have received scholarly attention at the Ruusbroec Institute.