The major source for the vows and sacrifices made annually on 3 January for the safety of a Roman emperor and his family, and on some other occasions in special circumstances, is in the Acta of the Arval Brothers which preserve, for a number of years in the first, second and third centuries A.D., accounts of these ceremonies as conducted by the Arvals, including the formulae of their prayers. There is literary evidence to show that similar ceremonies took place throughout the Empire, but for their form outside Rome nothing very detailed. Pliny reports their observance in his province in terms which reflect very summarily the general tenour of the prayers; and the Feriale Duranum, col. I lists the sacrifices to be made on the 3rd of January by a military unit in the early third century.