One of the panels shows the following, according to the official text:
"Sir Galahad's entry into the Castle is here shown.
The imprisoned maidens have long been expecting him,
for it had been prophesied that the perfect knight would
come to deliver them. They welcome him with shy
delight, putting out their hands to be kissed; behind
him lies his white shield bearing the red cross painted
with his own blood by Josephes, son of Joseph of
Arimathea. Having accomplished this mission, Sir
Galahad passed on to other deeds."
The murals have been restored and are open to the public.
Boston Public Library website info.
Full text explaining murals
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