A more thorough explanation:

De warrantia chartae (dee w-ran-shee- kahr-tee) is a legal term in Latin that means "of a warranty of charter." It refers to a writ that allowed a tenant who was impleaded in an assize or other action to compel the feoffor (the person who granted the land) to assist the tenant with a plea or defense, or else to pay damages and the value of the land if it is recovered against the tenant.

For example, if John grants land to Mary and warrants the title, and then Mary sells the land to Jane, who is later sued by a third party claiming ownership of the land, Jane can use the writ of de warrantia chartae to compel John to assist her with a plea or defense, or to pay damages and the value of the land if she loses the case.

This writ was used in the form of common recoveries, which were grounded on a writ of entry. In a writ of entry, the tenant vouches another person to warrant their title. If the tenant's title is weak, the voucher can be called upon to assist with a plea or defense. If the voucher fails to do so, they must pay damages and the value of the land if it is recovered against the tenant.

The examples illustrate how the writ of de warrantia chartae was used to protect tenants who were impleaded in an action and could not call upon the warranty. It allowed them to compel the feoffor to assist them with a plea or defense, or to pay damages and the value of the land if they lost the case. This writ was an important legal tool in medieval England and was used to protect tenants' rights and interests.