and only ever cared about religion as an excuse to murder people and take their land
No, some of them took it seriously and spent all their time growing new varieties of roses, surreptitiously waking up friends who fell asleep during sermons, and launching weird abortive crusades against low-ranking Muslim nobles who were briefly rebelling against the Caliph due to a tax increase.
One of the Tsars also married a member of the last Byzantine dynasty. Though a member of the dynasty with a stronger claim sold the title to the king of France and also left it in his will to Ferdinand and Isabella, so the French and Spanish monarchs claimed it for a while too. You'd think monarchs with actual power would refrain from giving themselves fake titles over land they don't control, because it kind of calls into question the legitimacy of their other titles, and because it might give ideas to people who want their land. But most of them seem to love giving themselves dozens of meaningless titles.
No, some of them took it seriously and spent all their time growing new varieties of roses, surreptitiously waking up friends who fell asleep during sermons, and launching weird abortive crusades against low-ranking Muslim nobles who were briefly rebelling against the Caliph due to a tax increase.