Triquetra

The triquetra is a symmetrical figure of three interlaced arcs forming a three-cornered knot, sometimes enclosed in a circle. As ornament it is ancient and widespread, appearing on Germanic and Scandinavian objects and on Insular manuscripts, and like most interlace it carried no fixed doctrinal meaning where it was first drawn. Its best-known early appearances are in Insular Christian art of the early medieval British Isles, in illuminated gospel books such as the Book of Kells, where a triquetra recurs among the trumpet-spirals and interlaced bands of the elaborate monogram page at folio 34 recto, and on carved stone crosses, where triple knotwork was congenial to a Christian culture that could read three-in-one designs in the light of the Trinity, though the artists rarely tell us they intended that.

Manuscript scholars generally treat the figure, in this period, as one interlace unit among many rather than as a captioned symbol set apart for special meaning, a caution worth keeping given how confidently later tradition reads doctrine back into it. Geometrically the shape is also described as three overlapping vesica piscis lens-shapes, the same lens formed by two intersecting circles that underlies a great deal of medieval compass-drawn ornament, which is part of why closely similar interlace patterns recur independently in artistic traditions that had no contact with one another.

From the medieval period the triquetra was increasingly read explicitly as a symbol of the Christian Trinity, three equal, distinct, inseparable arcs sharing one continuous line, and it is used in that sense in churches today, often labelled the Trinity knot. The nineteenth-century Celtic Revival recovered Insular knotwork as a marker of Irish and Scottish identity, and from the later twentieth century the triquetra was adopted by modern Pagan and Wiccan currents as a sign of a triple goddess or of threefold nature. Its single most concentrated push into wider recognition came from broadcast fiction rather than any Pagan text: the American television series Charmed, which ran from 1998 to 2006, used a triquetra within a circle as the emblem on its central prop, the Book of Shadows, and tied it to the show's central magical device, the Power of Three shared by its three witch protagonists, a fictional framing that nonetheless sent large numbers of viewers looking for the symbol's real-world Celtic and Wiccan associations. These modern meanings are genuine to the communities that hold them but are not continuous with the medieval usage; the claim that the triquetra is an ancient Celtic goddess symbol reads a recent interpretation back onto ornament that did not carry it.