Researchers have employed a novel artificial intelligence technique to reevaluate the authorship of El Greco's masterpiece, The Baptism of Christ. Historically, art historians have believed the 1614 work was unfinished at the artist's death and completed by his son, Jorge Manuel. However, new analysis suggests El Greco may have been more involved in the final stages than previously assumed. The study utilized a new algorithm called PATCH, or pairwise assignment training for classifying heterogeneity, published in Science Advances. El Greco, like many masters of his era, operated a workshop filled with skilled apprentices who assisted in creating commissioned pieces. This collaboration complicates modern attribution because a single canvas often contains variations in style. Traditional AI methods struggle with such scenarios due to the lack of a standardized reference library for unknown artists. To overcome this, the team developed PATCH, which utilizes high-resolution 3D imaging to map the microscopic texture of paint on a canvas surface. The technology captures the unique ridges and valleys left by an artist's brushstrokes. The algorithm then employs a convolutional neural network to compare adjacent one-centimeter square patches of paint. If the AI can easily distinguish between two patches, it indicates they were likely painted by different individuals. If the system finds them difficult to separate, the strokes probably originated from the same hand. This approach allows the tool to analyze hundreds of patches across a single work. The researchers noted that PATCH outperforms existing statistical and unsupervised machine learning methods, particularly in cases where there is no prior ground truth data to confirm authorship. Before applying the technology to the historic paintings, the team validated the method using twenty-five artworks created by nine students. The AI successfully identified the distinct hands of the different painters, confirming its accuracy. The study then applied PATCH to The Baptism of Christ and compared it with Christ on the Cross with Landscape, a work widely accepted as being almost entirely painted by El Greco himself. The results showed a high degree of consistency between the two paintings, indicating a generally uniform artistic hand at work rather than a distinct separation between the master and his workshop. While the findings challenge the long-held view that the workshop completed a significant portion of The Baptism of Christ after El Greco's death, the authors caution that the results are not definitive. The technique has limitations, as age-related damage and deterioration can affect the accuracy of texture mapping. Additionally, if apprentices were highly skilled at mimicking the master's style, the AI might fail to distinguish their work. Despite these constraints, the researchers argue that their study represents a significant advance in the scientific analysis of art history. The study provides a valuable new tool for art sleuths, offering a quantitative approach to resolving disputes over attribution. By focusing on the physical evidence of brushwork rather than just stylistic interpretation, this method opens new avenues for understanding the creative processes of Renaissance masters. The findings suggest that El Greco's direct involvement in his works may have been more extensive than current scholarship acknowledges, prompting a re-examination of his workshop's role.