"on crusade" is an acceptable phrase in written English.
It is usually used to refer to a campaign or cause that one is passionate about or devoted to. For example, "She's been on crusade to promote environmental activism in her community."
This account could be evidence that he died on crusade: one possibility is the First Crusade, perhaps in the entourage of Robert II, Duke of Normandy; another possibility is the so-called Norwegian Crusade, in the entourage of Sigurðr Magnússon, King of Norway.
Some time before 1290 Burnell vowed to go on crusade to help reinforce the crusader city of Acre, which was threatened by Muslims in the late 1280s, but he never fulfilled his obligation.
While on crusade, he was praised by his fellow crusaders, and acted as Richard's principal negotiator with Saladin for a peace treaty.
The quarrel continued until 1095, when Bohemond left on crusade.
Why have these authors gone on crusade for Harry?
Bolingbroke then went on Crusade into Lithuania (1390) and Prussia (1392).
After Richard's departure on crusade, he became joint justiciar with Hugh de Puiset, bishop of Durham (March 1190).
Edward began his reign with heavy debts incurred on crusade, and his various wars also were costly.
McGowan has been on crusade to speak out on sexism in Hollywood since getting fired following the 2015 casting incident.
Cannily, he surrendered England and Ireland to the Pope, by way of regaining his favor, and then pledged to go on crusade, for the same reason.
His body was buried in Dunfermline Abbey, but the heart was removed on his instructions and taken by Sir James Douglas on crusade in Spain.
