From the website:
This is an experimental service that makes the ICONCLASS Iconographic Classification system available as linked-data using the SKOS vocabulary. This service is inspired by the excellent Library of Congress Subject Headings linked data service. It is intentionally copied in spirit and conventions used. The idea is to enable others to make services that could make use of both underlying classification systems using the same toolings. And before you ask, yes I have been in contact with the creator of lcsh.info about this effort. More information about the Linked Data effort can be found on the W3C Wiki.
The service is still experimental (as noted above) and the dataset is incomplete. The dataset can be downloaded as a zip file. There is currently no information about re-using the data.
ICONCLASS - Multilingual Thematic Classification. No author.
Retrieved 04:03, Jun 19, 2013 (UTC).
the Data Hub