These measures of land make their appearance at an early period in the mythic history of Ireland, for it is recorded of Ollamh Fodla, one of the most remarkable figures who appears in this extraordinary catalogue of shadowy monarchs, and who is said to have flourished twelve centuries before Christ, that ‘it was he also that appointed a _Toisech_ over every _Tricha-ced_, and a _Brughaidh_ over every _Baile_, who were all to serve the king of Erinn.’[177] They emerge also in the historic period in the tenth century, when a great fleet of Danes landed at Limerick and plundered and ravaged Munster, both churches and tribes (_Cella_ ocus _Tuatha_), and their king is said to have ‘ordained kings (_Rigu_), chiefs (_Taishechu_), _Maers_ and _Reactdairidu_ or stewards in each land (_Tir_) and in each _Tuath_, as well as levied the _Cis rigda_, or dues of the kingdom,’ that is, confirmed the old tribal organisation, substituting Danes for Gael, so that there was ‘a king (_Ri_) for each _Tir_, a _Toisech_ for each _Tuath_, an abbot for each _Cill_ or church, a _Maer_ for each _Baile_, and a _Suairtleach_ in each _Tigi_ or homestead.[178] In the succeeding century it is told of Brian Boroimhe, the Munster king who reigned over Ireland from 1002 to 1014, and defeated the Danes in the great battle of Clontarf, that ‘during his time surnames were first given, and territories (_Duchadha_) allotted to the surnames, and the boundaries of every _Tuath_ and every _Tricha-ced_ were fixed.’[179] But although these ancient measures of land are represented as possessing a definite and fixed extent, yet there seems to be little doubt that they varied very much in different parts of Ireland. Thus the unit of the _Seisrigh_ or ploughgate seems to have been of two kinds—a larger measure of 120 acres in some parts of Ireland, and a smaller measure of 60 acres in other parts. We also find the _Ballybiatagh_ consisting of sixteen _Taths_ in place of twelve ploughgates, the _Tath_ containing sixty acres. [Sidenote: Later state of the tribes.]