The Gawain-Poet was familiar with the pentangle and made much of its Christian and knightly symbolism.  He was not only familiar with the pentangle, but he regarded it as important enough to justify a lengthy diversion (lines 620-665) from his story in Sir Gawain and the Green Knight

From Hardman [HARDMAN99] we learn that the use of the pentangle symbol in England in the late fourteenth century was extremely rare, and that the English church itself associated the symbol with heathen and magical practices.  Such knowledge of, or imaginative use of, the symbolism of the pentangle was a very unlikely attainment in the north west of England, and also a very rare one in London.^[9]

The arms of Sir Gawain consisted of a gold pentangle on a red background

Following the death of his patron, Philippa of Lancaster (Queen Félipa, of Portugal) in 1415, James Cottrell was very closely associated with the Order of Christ at the Castle of Tomar in Portugal.  James Cottrell was not one of the brethren, but was appointed Monteiro-Mór (head hunter or master forester) to the new lay Master of the Order, the Infante Dom Henrique, the Navigator, to whom he had been tutor.  The Pentangle was an important symbol of the Order, derived originally from the Templars whom they succeeded, and the pentangle symbol was inscribed in the windows of their chapel and on the graves of dead brothers, where it can still be seen today (see Section D.3.)^[10]  Admittedly all this experience was a few years later than the supposed date of the Nero A.x manuscript, but James Cottrell had replaced Dom Lopo Dias de Sousa (who was also the last elected Master of the Order of Christ) as Mordomo-Mór at the royal household as early as 1387, had shared with him the tutoring of the princes, and had married his son, Lopo (was he named after Lopo de Sousa?), to Dona Isabel de Sousa, daughter of Gonçalo de Sousa.  His son Lopo became Monteiro-Mór of Dornes which had a church with an unusual pentagonal tower built by the Templars in the thirteenth century.  We must conclude that he had close contact with the Order of Christ and the pentangle prior to 1390.

The arms of the family of James Cottrell consisted of three gold mascles on a blue background (Azure, three mascles or,) and those of the Catteralls of Rathmell in Ribblesdale also included “over all a bendlot gules”.  These three mascles can be re-arranged to fit a gold pentangle (see Section D.1.)  Poor evidence, but no worse than relating mascle to Masci [GREENWOOD56].  The arms James Cottrell assumed in Portugal were a blue and gold chessboard (see Section D.2.), striking a memory of Sir Gawain in Wolfram's Parzival having to defend himself with a chessboard when he didn't have a shield to hand.