Not all the petty states were subject to tribute. When the dynasty of a petty state was a branch of the over-king's dynasty, no tribute was due. In Munster, for example, there were various petty states whose rulers were of the Eoghanacht lineage. These paid no tribute to the king of Cashel, who was also of Eoghanacht lineage. The other states were tributary. This exemption from tribute and liability to tribute goes back to an ancient state of conquest, but of conquest during the Celtic period. The citizens of the tributary states were freemen, whereas the people of the older communities of pre-Celtic origin were, at least in theory, unfree. This does not mean that they were slaves. The status of the unfree communities, roundly speaking, was similar to that of the natives of British India at present; and the status of a tributary state would be comparable to that of a country possessing self-government but subject to what is called an imperial contribution. The non-tributary states might be compared to the existing autonomous dominions of the British Empire. There were distinct names for each class. Non-tributary states were called _saor-thuatha_, "free states"; tributary states were called _fortuatha_, which means "alien states"; unfree communities were called _daor-thuatha_, which we might translate "vassal-states"--and they were also called _aithech-thuatha_, "rent paying states." Each free or tributary state had a distinct territory, but the unfree communities were not bounded by the territorial bounds of the others. They might overlap the bounds of two or more States, and some of them were broken into separate groups distributed here and there over a very wide area. The compilation of the Book of Rights is ascribed to two writers, Selbach and Oengus, acting under the authority of Cormac mac Cuilennáin, king of Munster. Cormac reigned from 901 to 908. As O'Donovan has shown, the Book received certain amplifications under a king of Munster who claimed to be, or aimed to make himself, king of Ireland; and O'Donovan properly argues that this king could only be Brian Bóramha. Moreover I think that there are fairly clear indications of the year 1000 or 1001 as the date of these amplifications.