One of the most interesting studies and not yet finished, it is referring to the graves there in the Basilica.
"The graves of the Basilica of the Virgin of Mercy." ("Les sepultures de la Basílica de la Mare de Déu de la Mercè")., Jordi Bonet Armengol. A. Bulletin Catalan Royal Academy of Fine Arts in St. George, No. XV (2001) p. 275-288
The inscription on the gravestone of one of the arches linking the church with captain there is this inscription:
"This is the first monastery of the Order of the Virgin Mary of Mercy founded X August. M CC XVIII "