I yield to nobody
The Romans worshiped in the figure of the god Terminus the sanctity of boundary stones. According to legend (Livy, 1.55), when king Tarquin began construction of the temple of Jupiter on the Capitol, he ordered the removal of the altars and shrines of all the gods that were worshiped there, so the area could be devoted exclusively to the king of the gods. All were transferred without problems, except for Terminus, represented with a stone that could not be removed. The Romans saw in this fact a manifestation of divine will, and let the rock inside the temple. Hence the expression "I yield to no one", because Terminus had refused to yield to Jupiter himself. This fact was interpreted as an omen, meaning that the dominion of Rome would be everlasting. The prophecy proved valid for centuries.
The celebrity of the sentence “concedo nulli” is due to Erasmus, who took it as a personal motto in 1509, adopting the old god Terminus as its emblem. The young Erasmus was then in Italy, and began to enjoy international recognition for his work and abilities. Apparently, Erasmus received from his pupil Alexander Stewart a gem depicting the god Terminus, and this is what inspired him to take the image of the god and the Latin quotation discussed here as personal emblems. They appear in a famous commemorative medal minted for Erasmus, whose image you see below. Erasmus is also shown next to the god Terminus in a famous engraving by Holbein.
Erasmus' enemies saw this motto as a sign of intolerable arrogance. In 1528 Erasmus wrote a letter justifying his choice of these words and trying to disarm his critics: the "epistola apologetica de Termini sui inscriptione concedo nulli" There, the great humanist stated that the term did not represent his own words, but those of death, the only one that yields to nobody. But this explanation did not satisfy his enemies. Written almost twenty years after the original stay of Erasmus in Italy, it seems, in fact, a later reworking. Humility was never one of Erasmus virtues. Posterity has been, however, more benign in judging Erasmus than his contemporaries.