About tree frogs and man. Part 1: Cultural historical aspects Through the centuries, the European tree frog (Hyla arborea) in Europe has had an intensive relationship with man and his culture. In this first of two articles, the culturalhistorical aspects of this relationship are highlighted. In a second article, we will go into the cultural influence on the distribution of the tree frog in Western Europe. Probably from at least Roman times onwards (but certainly since the Middle Ages) up until the beginning of the 20th century tree frogs were used as forecast of changes in the weather. Often tree frogs were kept in captivity for this purpose in large glasses. Croaking tree frogs or tree frogs sitting at the bottom of the glass were believed to predict rain. Furthermore, tree frogs were used as medicin for a broad spectrum of ‘disseases’, as afrodisiacum, as goodluck charm or just for fun. Mostly, the frogs did not survive such applications. They were also considered poisonous for dogs and cattle, but also good bait for fishing. The pagan tradition to celebrate the coming spring by dressing up as a tree frog is believed to be an important reason for the Roman Catholic Church to designate this frog as a diabolic species. For herpetologists, however, this forecast of spring is a heavenly gift.