MOA2/METS History

METS originated in a project that identified metadata and complex digital object structure as an area of critical concern for digital libraries. As more and more institutions digitized portions of their collections, there was growing concern about how to express the structural relationships between the digital files and data that together comprise a single digital object or entity.

The Making of America II (MOA2) project sponsored by the Digital Library Federation (DLF) in the early stages and funded by the National Endowment for the Humanities resulted from these discussions. New York Public Library and the libraries of Cornell, Penn State, and Stanford Universities collaborated under the leadership of the UCB Library on an investigation of how to encode structural, descriptive and administrative metadata for digital objects. The project produced the MOA2 XML Document Type Definition (DTD), the direct predecessor of METS, to specify a vocabulary and syntax for encoding digital objects.

After the MOA2 project ended in early 2000, the Council on Library and Information Resources (CLIR) published the group's findings, and the MOA2 DTD was circulated for assessment and discussion. While MOA2 aroused considerable interest within the library community, the MOA2 DTD was too restrictive in some respects and lacked some basic functionality, especially for time-based media such as audio and video. In February, 2001, interested institutions started to meet to build on the groundwork laid by the MOA2 project. The METS schema has come out of this work.