St Martin of Tours - a fourth century soldier turned bishop, is one of the more familiar saints in medieval art, best known for cutting his cloak in half to clothe a shivering beggar. His extensive vita was largely penned during Martin's lifetime by his friend Sulpicius Severus - a talented writer who exemplified the late Classical panegyrist literary style. For the most part the secondary writers on Martin followed Sulpicius closely, though the fact that his vita predates the saint's death meant that details of his demise and posthumous fortunes had to be drawn from the later dialogues of Sulpiius and other sources, some of which were drawn together by Voraginus.
Martin's first position within the church was as an exorcist and it is his power to overcome demons, combined with his zeal in combatting heresy that stand out both in Sulpicius' text and in the window. The saint's popularity at the start of the 13th century was boosted by the renewed fear of heresy and by the 'muscular evangelism' of campaigns like the Albigensian Crusade (in which the Bishop of Chartres was an enthusiastic participant) which that fear fed.
The designer of this window at Chartres has followed the events in Sulpicius quite closely, in most cases retaining the original order of the episodes. The arrangement of the panels is particularly noteworthy; the window is divided into four regular square sections (plus an extra half section in the summit), each comprising a central circle and four corner-squares arranged as a quincunx. The four cardinal points are filled with smaller quatrefoil medallions surrounded by vegetal rinceaux. With the exception of the lowest section, where they house the 'signature panels', these lesser medallions contain hypotactic (to borrow Wolfgang Kemp's term) elements - pairs of figures or censing angels - which contribute to or comment upon the adjacent major panels and in one case (panel 26) act as a linkage, or 'copula' to show that to separate panels are part of the same scene..