Camps of people were disposed in the lordly gardens of Cæsar, formerly gardens of Domitius and Agrippina; they were disposed also on the Campus Martius, in the gardens of Pompey, Sallust, and Mæcenas, in porticos, tennis-courts, splendid summer-houses, and buildings erected for wild beasts.
Tennis courts? Per Wikipedia, tennis in its earliest form was recognized in 12th century.
