Roman usages, but may equally have been intended to increase royal power over the church. Nonetheless, the evidence of place names suggests a wide area of Ionan influence in Pictland. Likewise, the Cáin Adomnáin (Law of Adomnán, Lex Innocentium) counts Nechtan's brother Bridei among its guarantors. The importance of monastic centres in Pictland was not, perhaps, as great as in Ireland. In areas that have been studied, such as Strathspey and Perthshire, it appears that the parochial structure of the High Middle Ages existed in early medieval times. Among the major religious sites of eastern Pictland were Portmahomack, Cennrígmonaid (later St Andrews), Dunkeld, Abernethy and Rosemarkie. It appears that these are associated with Pictish kings, which argue for a considerable degree of royal patronage and control of the church. Portmahomack in particular has been the subject of recent excavation and research, published by Martin Carver. The cult of saints was, as throughout Christian lands, of great importance in later Pictland. While kings might venerate great saints, such as Saint Peter in the case of Nechtan, and perhaps Saint Andrew in the case of the second Óengus mac Fergusa, many lesser saints, some now obscure, were important. The Pictish Saint Drostan appears to have had a wide following in the north in earlier times, although he was all but forgotten by the 12th century. Saint Serf of Culross was associated with Nechtan's brother Bridei. It appears, as is well known in later times, that noble kin groups had their own patron saints, and their own churches or abbeys. Art Pictish art appears on stones, metalwork and small objects of stone and bone. It uses a distinctive form of the general Celtic Early Medieval development of La Tène style with increasing influences from the Insular art of 7th and 8th century Ireland and Northumbria, and then Anglo-Saxon and Irish art as the Early Medieval period continues. The most conspicuous survivals are the many Pictish stones that are located all over Pictland, from Inverness to Lanarkshire. An illustrated catalogue of these stones was produced by J. Romilly Allen as part of The Early Christian Monuments of Scotland, with lists of their symbols and patterns. The symbols and patterns consist of animals including the Pictish Beast, the "rectangle", the "mirror and comb", "double-disc and Z-rod" and the "crescent and V-rod", among many others. There are also bosses and lenses with pelta and spiral designs.