In a fuzzy topology on a set X, the limit of a prefilter (i.e. a filter in the lattice [0,1]X) is calculated from the fuzzy closure. In this way convergence is derived from a fuzzy topology. In our paper we start with any rule ΒlimΒ which to any prefilter π on X assigns, a function limπβ[0,1]X. We give necessary and sufficient conditions for the function πβlimπ in order that it can be derived from a fuzzy topology.