Pliny and Columella report the passion of the emperor Tiberius (14-37 A.D.) for cucumbers. Columella describes a sort of "mobile" greenhouse that was placed in the sun when needed. It was practical and economical, and required no particular preparations. Pliny the Elder instead describes a "fixed" greenhouse consisting of a static structure enclosed by glass where little carts holding the plants were placed. According to these authors, both models were made for the forced production of cucumbers: the first was probably a seedbed, while the latter was used to accelerate growing time.