The chief sphere remained that of civic religion, embodied in the festivals: M.I. Finley notes "in Demosthenes' day there were at least 97 liturgical appointments in Athens for the festivals, rising to 118 in a (quadrennial) Panathenaic year."[3] However, groups of rich citizens were assigned to pay for expenses such as civic amenities and even payment of warships. Eventually, under the Roman Empire, such obligations, known as munera, devolved into a competitive and ruinously expensive burden that was avoided when possible. These included a wide range of expenses having to do with civic infrastructure and amenities; and imperial obligations such as highway, bridge and aqueduct repair, supply of various raw materials, bread-baking for troops in transit, just to name a few.