A method for converting a legacy document into an XML document, includes decomposing the conversion process into a plurality of individual conversion tasks. A legacy document is decomposed into a plurality of document portions. A target XML schema including a plurality of schema components is provided. Local schema are generated from the target XML schema, wherein each local schema includes at least one of the schema components in the target XML schema. A plurality of conversion tasks is generated by associating a local schema and an applicable document portion, wherein each conversion task associates data from the applicable document portion with the applicable schema component in the local schema. For each conversion task, a conversion method is selected and the conversion method is performed on the applicable document portion and local schema. Finally, the results of all the individual conversion tasks are assembled into a target XML document.