Why does the portrait that was absent in art for nearly 1000 years return during the 15th century?

The return of portraiture in the 15th century can be attributed to the Renaissance's renewed interest in Humanism and individualism, emphasizing the importance of the individual and their personal identity. This period saw a shift in artistic focus from religious themes to secular subjects, as artists began to explore the complexities of human emotion and personality. Additionally, advancements in techniques such as oil painting allowed for greater realism and detail, making portraits more appealing and accessible to patrons seeking to commemorate their likeness and status.