The Basilica of Assisi (Italy), built in 1228, has been a UNESCO World Heritage Site of unparalleled historical and artistic value since 2000. Located in one of Italy’s most seismically active areas, it suffered severe damage during the 1997 earthquake (Mw 6.0), when part of the nave collapsed. The Basilica was carefully restored over the following years. To safeguard this iconic structure, the authors implemented a comprehensive long-term monitoring system on the vaults and bell tower between 2022 and 2023. The sensor network includes LVDTs (Linear Variable Differential Transformers) installed on the vaults of the Upper Basilica, six triaxial ultra-low-noise QMEMS Epson M-A552 accelerometers placed at three levels of the bell tower, and an INGV OSU seismic station, equipped with an ETL3D/5s velocimeter and ultra-low-noise QMEMS Epson M-A352 accelerometers, installed at the base of the structure. All collected data, managed through the Wise Robotics cloud-based platform for efficient analysis and accessibility, contribute to identifying the structure’s dynamic behaviour and potential anomalies. This research correlates recent seismic events with vault's displacements and the modal properties of the bell tower. Looking ahead to future expansion of the monitoring network, the project contributes to the preservation of the Basilica of Assisi and in advancing knowledge of the long-term behavior of monumental structures under complex loading conditions.