In Don Gaspar de Guzmán (1587–1645), Count-Duke of Olivares, Diego Velázquez presents a striking portrait of the influential Spanish nobleman. The painting features rich, deep colors, with a predominance of dark tones that highlight the figure's serious expression. Guzmán is depicted in elaborate attire, adorned with a lace collar and a dark cloak, which emphasizes his status.

The background is subtly rendered, focusing attention on the subject while suggesting a sense of depth. The painting is executed in oil on canvas, a common medium for Velázquez, allowing for detailed textures and rich color saturation. The dimensions are approximately 100 x 120 cm, making it a sizable portrait that commands attention. Velázquez's technique showcases his ability to capture the nuances of light and shadow, giving the figure a three-dimensional quality.

The brushwork is both precise and fluid, contributing to the overall realism of the piece. Diego Velázquez, a leading figure of the Spanish Baroque, created this portrait around 1635 during his time at the court of King Philip IV. This work is notable not only for its artistic quality but also for its historical significance, as Guzmán was a key advisor to the king and a central figure in Spanish politics. An interesting fact about this painting is that it reflects Velázquez's innovative approach to portraiture, moving away from traditional representations to convey personality and presence.

The work remains a testament to the artist's skill and the importance of Guzmán in Spanish history.