Lower Basilica of San Francesco, Medieval Catholic church in Assisi, Italy

The Lower Basilica of San Francesco is entered from the lower square through a Gothic twin portal completed before 1271, set under a Renaissance portico by Francesco di Bartolomeo da Pietrasanta with a mosaic of the blessing saint. Inside, a single nave of five bays has ribbed cross vaults and a transept closed by barrel vaults; the plan forms a Tau cross. The first bay was lengthened into a long narthex, at whose ends stand the polygonal chapels of Santa Caterina and Sant'Antonio Abate.

Construction started in 1228 after the canonization of Francis, with Pope Gregory IX laying the foundation stone. The saint's body was secretly placed in the foundation in 1230 to prevent relic theft.

The paintings on the walls tell stories from the Bible and episodes from the saint's journey, serving as teaching tools for worshippers who could not read. Visitors today can see how medieval artists used color and composition to transform stone interiors into narrative spaces.

The entrance is on the lower square of San Francesco; because the hill slopes, the portal opens directly into the left side of the nave rather than its centre. The floor tilts slightly toward the main altar, and the side chapels block the nave windows, so the interior stays dim. The cemetery cloister with its two orders of loggias, built by Pietro and Ambrogio in 1492-1493, is reached through a door in the left wall of the Sant'Antonio Abate chapel.

The rediscovery of the remains in 1818 happened after nearly 600 years of concealment beneath the floor. Pasquale Belli then designed a new crypt that allowed access to the tomb and reshaped the underground space.