A more thorough explanation:

Definition: Assisa de utrum is a Latin term that refers to a writ used in medieval England to determine whether land claimed by a church was held by lay or spiritual tenure. The writ is named after its emphatic word, which required the fact-finder to determine whether the land belonged to the church.

Example: In the assisa de utrum, a jury was summoned to decide whether land was held by lay or spiritual tenure. This was a preliminary question to any litigation about it, for the Church claimed jurisdiction over spiritual land. Later, the Church lost this jurisdiction, and the assisa de utrum became the parson's substitute for the writ of right.

Explanation: The example illustrates how the assisa de utrum was used to determine the ownership of land claimed by the Church. The writ was important because it was the first instance known to us of the general use of the royal procedure by way of inquest in a matter of private litigation. If the answer of the inquest was that this land was held in frankalmoign, then the case went to the ecclesiastical court; if that it was lay fee, then to the appropriate lay tribunal.