The Era of Manifestations, also called Mother Ann's Work, began at Watervliet in August 1837 when adolescent girls began shaking, singing unknown songs and reporting visits from Mother Ann. It spread to every community and lasted into the 1850s. Spirits brought songs — thousands of them, written down in a Shaker letteral notation — along with drawings, secret alphabets, and gifts of spiritual food and clothing distributed in meeting. Communities laid out outdoor feast grounds with a marked stone and held ceremonies there. The Ministry was ambivalent throughout: the manifestations restored fervour to a society that had become prosperous and orderly, and they also handed authority to teenage girls, which the elders found difficult. The gift drawings, particularly Hannah Cohoon's Tree of Life of 1854, are now the most reproduced Shaker artefacts after the furniture, and were made by people who did not consider themselves artists and did not sign them as such.