Spannocchi had been named Treasurer to Pope Pius II of the Sienese Piccolomini Family.
The facade closely parallels the Palazzo Medici Riccardi of Florence built a few decades prior.
The sober facade, of smooth stone, has three stories, with mullioned windows with round arches on the second floor.
It faces a square with a statue of the Sienese scholar Sallustio Bandini (1882) by Tito Sarrocchi.
This entire square was reformulated in the 19th century by removing a garden found in front of the Spannocchi palace.