Which medieval romance first introduced a mysterious Grail procession featuring a bleeding lance?

Perceval, le Conte du Graal first introduced the famous mysterious Grail procession featuring a bleeding lance.

Chrétien de Troyes’s Old French romance presents Perceval visiting the Fisher King. During a strange procession, a bleeding lance and a richly decorated grail pass before him, but Perceval fails to ask the compassionate question that might have helped the wounded king.

Chrétien does not clearly identify the Grail as the cup used at the Last Supper. Later authors, especially Robert de Boron and the prose Grail cycles, added stronger Christian meanings and connected the object with biblical history.

The bleeding lance is also distinct from the Grail itself. Readers sometimes merge the two because later Grail narratives place several sacred objects together in ceremonial scenes.