  Iconography and iconology are fundamental domains when it comes to
understanding artifacts of cultural heritage. Iconography deals with the study
and interpretation of visual elements depicted in artifacts and their
symbolism, while iconology delves deeper, exploring the underlying cultural and
historical meanings. Despite the advances in representing cultural heritage
with Linked Open Data (LOD), recent studies show persistent gaps in the
representation of iconographic and iconological statements in current knowledge
graphs (KGs). To address them, this paper presents IICONGRAPH, a KG that was
created by refining and extending the iconographic and iconological statements
of ArCo (the Italian KG of cultural heritage) and Wikidata. The development of
IICONGRAPH was also driven by a series of requirements emerging from research
case studies that were unattainable in the non-reengineered versions of the
KGs. The evaluation results demonstrate that IICONGRAPH not only outperforms
ArCo and Wikidata through domain-specific assessments from the literature but
also serves as a robust platform for addressing the formulated research
questions. IICONGRAPH is released and documented in accordance with the FAIR
principles to guarantee the resource's reusability. The algorithms used to
create it and assess the research questions have also been made available to
ensure transparency and reproducibility. While future work focuses on ingesting
more data into the KG, and on implementing it as a backbone of LLM-based
question answering systems, the current version of IICONGRAPH still emerges as
a valuable asset, contributing to the evolving landscape of cultural heritage
representation within Knowledge Graphs, the Semantic Web, and beyond.
