It is unlikely that the words "preserverance" or "diligence" spring readily to mind when one thinks of chivalry -- which is why I find them so insightful additions to the list of knightly virtues. Of course, if one looks at the romances of the Age of Chivalry, these virtues are represented in abudance. The heroes of chivalry were on a quest for greater glory, honor or love and they usually encounter many difficulties along the way. Without perserverance and diligence, success would be impossible.
Real life in the High Middle Ages also required a great deal of preserverance and diligence. Knights were not born: they were made by years and years of service and training as pages and squires. Few men were knighted before they had endured many falls in the tiltyard, endless banquets requiring an understanding of protocol and manners, and hours of classroom instruction learning reading, writing, accounting and more.
Balian d'Ibelin must have had more than his fair share of both of these virtues. As younger son he probably had to work harder to make his way in the world as a young man. Which may explain why he was so tenacious as an older man. What is certain is that having lost his entire inheritance in 1187, he diligently rebuilt his fortunes -- step by step and marriage by marriage -- until the once obscure and insignificant family had become the most powerful in the Latin east. The House of Ibelin was so predominant and so influential, in fact, that Ibelins more than once challenged ruling monarchs, including the Holy Roman Emperor. They served as regents and constables, and their daughters married kings.