As the record improves, and the body of scholarship increases, the need for multi- and interdisciplinary working becomes increasingly apparent. Several major multi-disciplinary collaborative studies have been published on important individual monuments (e.g. St Andrews Sarcophagus–Foster 1998a; Henderson 1994; Ruthwell Cross–Cassidy 1992; Ó Carragáin 2005; Orton et al. 2007; Hilton of Cadboll cross-slab–James et al. 2008; Stone of Destiny–Welander et al. 2003; Rodwell 2013). See also the smaller collaborative studies by Hall et al. 2000; 2005; 2011. In addition to art-historical and archaeological approaches, these studies have drawn, for instance, on history, including oral history, ethnography, and social history, as well as various scientific disciplines (Figure 25) (Case Study 18: Strength in disciplinary collaboration: early medieval examples). New theoretical and transdisciplinary approaches are increasingly applied (see Section 3.7.2), for instance: 'biography' (Clarke 2007; Foster and Jones 2008; Hall 2012a; 2015a); landscape (Inglis 1987; Forsyth and Driscoll 2009; Fraser and Halliday 2011; Gondek and Noble 2011); experiential (Pulliam 2013; Gefreh 2015).
The tremendous potential of this material is becoming increasingly evident and there is great scope for future research of all kinds–pursuing existing approaches and developing new ones, and picking up on older questions which have been neglected, for example the question of carving technique which has not been addressed directly since Gordon's 1956 study of 'Class I' Pictish symbol stones. There is also a renewed interest in geometric ornament (Garrett 2009; Hull 2003; Stevick 2010; Thickpenny in prep). Hints at the future direction of the field are provided by a number of PhDs in progress or recently completed: Comparative approach Scotland, Ireland and Sweden (Busset 2016); Southern Scotland and northern England in the Viking Age (Barnes in prep); 3D scanning (Kasten in prep); Key-pattern (Thickpenny in prep); Iona high crosses in the natural and liturgical landscape (Gefreh 2015); Reproductions (McCormick 2010).
Figure 25: Detail of the St Andrew's Sarcophagus. Scientific analysis identified the white/blue layer as lead-white, likely applied when plaster casts were created from the sculpture in 1839. © Sally Foster