The dedication of the hospice to the Holy Trinity and St Thomas of Canterbury goes back to its earliest days. The confraternity at the hospice went by the name of the Holy Trinity by 1371, and in 1373 a donation was made ‘out of reverence for Almighty God and the glorious Ever Virgin Mary, the Holy Trinity and blessed Thomas of Canterbury’
The ‘Mercy Seat’
The iconography of the Trinity which is invariably associated with the Hospice and later the College is that of the Mercy Seat. This imagery, shown below (1) on the frontispiece of John Clerk’s account book of 1523. The same image is seen on the hospice seal (2) and, of course on Durante Alberti’s 1581 Holy Trinity Altarpiece (3), more commonly known as the Martyrs' Picture.
This medieval image is also seen in an alabaster sculpture, the 13th-century ‘Black Abbey Trinity’, a copy of which (4) was commissioned for the College for the exhibition of 2009-10, celebrating the various restorations which had taken place. Alberti’s depiction is slightly unusual in that the crucified Son is depicted without the Cross. It also contains the additional Trinitarian symbolism of a triangular halo behind the Father’s head.
St Thomas of Canterbury
St Thomas, Archbishop of Canterbury, was murdered in his own cathedral by the knights of Henry II in 1170 who took literally Henry’s frustrated cry "who will rid me of this turbulent priest”. Canonised in 1173, popular devotion to him was widespread. He arguably had even greater significance for the College, since he was one who stood up for the rights of the Church over against the crown.
Circignani's Martyrdom of St ThomasThomas appears both on Clerk’s frontispiece and on Alberti’s altarpiece, in both cases at 5 below and with mitre cast down and the instrument of his martyrdom—a sword—depicted. It seems likely that Alberti’s arrangement was inspired by the image in Clerk’s book. Two other images of St Thomas in the College are also notable—Troppa’s altarpiece in what is known know as the Martyrs Chapel (6) , and the copy of Circignani’s 1583 fresco in the tribune of the church (5)