This dataset for monitoring the masonry of Aula I at the Baths of Diocletian (Rome) was created by the University of Tuscia. The measurements are carried out with a prototype based on Arduino UNO, have been investigated: Temperature and Relative Humidity of the internal environment and Temperature and Relative Humidity of contact on the masonry (with two sensors DHT22 AM2302); Acceleration along the three spatial axes (X, Y and Z), Pitch Index and Roll Index (with Gy 521 sensor); Surface pressure for the movement of a lesion (with FlexiForxe sensor). The data produced by the sensors were acquired and sent to the computer which automatically saved them every 10 seconds. The dataset is composed of the data obtained from 2017 to 2019 and separated by month in 11 sheets. In total about 40 million values were recorded, used to understand the slow hazard phenomena present on the monitored masonry. STORM (Safeguarding Cultural Heritage through Technical and Organisational Resources Management) is a HORIZON 2020 funded European Union Cultural Heritage project that aims at the protection of Cultural Heritage through a combination of technical and organizational resources (http://www.storm-project.eu).