Various methods of transporting children have been used in different cultures and times. These methods include baby carriages (prams in British English), infant car seats, portable bassinets (carrycots), strollers (pushchairs), slings, backpacks, baskets and bicycle carriers. The large, heavy prams (short for perambulator), which had become popular during the Victorian era, were replaced by lighter designs during the latter half of the 1900s. Baskets, slings and backpacks Infant carrying likely emerged early in human evolution as the emergence of bipedalism would have necessitated some means of carrying babies who could no longer cling to their mothers and/or simply sit on top of their mother's back. On-the-body carriers are designed in various forms such as baby sling, backpack carriers, and soft front or hip carriers, with varying materials and degrees of rigidity, decoration, support and confinement of the child. Slings, soft front carriers, and "baby carriages" are typically used for infants who lack the ability to sit or to hold their head up. Frame backpack carriers (a modification of the frame backpack), hip carriers, slings, mei tais and a variety of other soft carriers are used for older children. Images of children being carried in slings can be seen in Egyptian artwork dating back to the time of the Pharaohs, and have been used in many indigenous cultures. One of the earliest European artworks showing baby wearing is a fresco by Giotto painted in around 1306 AD, which depicts Mary carrying Jesus in a sling. Baby wearing in a sling was well known in Europe in medieval times, but was mainly seen as a practice of marginalised groups such as beggars and Romani people. A cradleboard is a Native American baby carrier used to keep babies secure and comfortable and at the same time allowing the mothers freedom to work and travel. The cradleboards were attached to the mother's back straps from the shoulder or the head. For travel, cradleboards could be hung on a saddle or travois. Ethnographic tradition indicates that it was common practice to cradleboard newborn children until they were able to walk, although many mothers continued to swaddle their children well past the first birthday. Bound and wrapped on a cradleboard, a baby can feel safe and secure. Soft materials such as lichens, moss and shredded bark were used for cushioning and diapers. Cradleboards were either cut from flat pieces of wood or woven from flexible twigs