The origins of "tributum" are traditionally linked to the Siege of Veii (406 – 398), in which the fund was used to pay soldiers. The Siege of Veii was described as a campaign in which the army served for a time longer than usual, prompting the Senate to decree Dionysius also comments on the origins of "tributum", however, notes that “due to a lack of reliable sources, it is impossible to describe or date with any degree of certainty either the genesis of the system or its subsequent development into the complex structure which Livy and Dionysius describe”. Furthermore, both Dionysius and Livy argue that tributum was an element of the Servian system, with its introduction occurring in the sixth century under Servian reign. This view is not supported, with warfare in Rome's early city-state considering military service as an obligation without remuneration ("stipendium") for soldiers. However, "tributum" and "stipendium" appear inextricably linked, with stating “theoretically, "tributum" could have existed prior to the war against Veii… the two institutions were so closely connected that imagining the one without the other is hardly feasible”.