Authenticating unsigned or undocumented bronze sculptures requires a multifaceted approach combining scientific analysis, historical research, and expert evaluation. Here are the most effective methods:

1. Material Analysis: Advanced techniques like X-ray fluorescence (XRF) or metallurgical testing can determine the alloy composition, patina authenticity, and casting methods, revealing inconsistencies with claimed origins.

2. Provenance Research: Tracing ownership history through archives, auction records, or collector documentation helps establish legitimacy, even if the artist’s signature is missing.

3. Stylistic Examination: Comparing the sculpture’s style, motifs, and craftsmanship to known works by suspected artists can identify attributions. Experts often detect subtle artistic fingerprints.

4. Microscopic and Patina Analysis: Authentic aging patterns, corrosion layers, and wear marks differ from artificially aged forgeries. Microscopy reveals telltale signs of modern tools or chemicals.

5. 3D Imaging and Comparative Studies: Digital scans can match undocumented pieces to documented ones in museum databases, uncovering hidden connections.

For high-value pieces, consulting certified appraisers or institutions like the International Foundation for Art Research (IFAR) adds credibility. Combining these methods minimizes the risks of misattribution or forgery.