"A commission to create a portal for Paris' planned Museum of Decorative Arts was awarded to Rodin in 1880. Although the museum was never built, Rodin worked throughout his life on The Gates of Hell, a monumental sculptural group depicting scenes from Dante's Inferno in high relief. Often lacking a clear conception of his major works, Rodin compensated with hard work and a striving for perfection.
...
The Gates of Hell comprised 186 figures in its final form Many of Rodin's best-known sculptures started as designs of figures for this composition such as The Thinker, The Three Shades, and The Kiss, and were only later presented as separate and independent works. Other well-known works derived from The Gates are Ugolino, Fugit Amor, The Falling Man, and The Prodigal Son.
The Thinker (originally titled The Poet, after Dante) was to become one of the most well-known sculptures in the world. The original was a 27.5-inch (700 mm)-high bronze piece created between 1879 and 1889, designed for the Gates' lintel, from which the figure would gaze down upon Hell. While The Thinker most obviously characterizes Dante, aspects of the Biblical Adam, the mythological Prometheus. and Rodin himself have been ascribed to him. Other observers de-emphasize the apparent intellectual theme of The Thinker, stressing the figure's rough physicality and the emotional tension emanating from it."

en.wikipedia.org