Bartolomé Esteban Murillo (1617-1682) : paintings from American collections
    Stratton, Suzanne L.
Publisher:    H.N. Abrams, in association with the Kimbell Art Museum,    
Pub date:    2002.    

Mueillo’s paintings for the church of the Hospital de la Caridad in Seville, completed between 1667 and 1670, represent, as an ensemble, his acknowledged masterpiece.

The ravenous appetite of foreign collectors for works by Murillo led the conde de Floridablanca to decree on October 5, 1779, on orders from King Carlos III, an absolute embargo on the exportation of his works from Spain.  (p73)

In 1810 the “intruder king” Joseph Bonaparte ordered the pictures gathered for safekeeping in the old Alcàzer of Seville, whence they were intended to be sent to the Louvre.  Five of those paintings were “conveyed” to Paris by Marshal-General Soult in 1812, but they were installed in his house, not the Louvre. (p148)

However, Spanish paintings in French collections were rarities until the Peninsular War, when French troops removed hundreds of works from churches and monasteries of Spain to France.  The French Republic legitimized the artistic plunder of its generals, even lending it an altruistic gloss:  “The French Republic, on account of its strength, the superiority of its intellectuals and its artists, is the only country in the world that can provide a secure exile for these masterpieces.” P92

Soult efficiently amassed 180 Spanish paintings, including twenty of Murillo’s finest works.  He was aided by two contemporary works which listed site by site, and city by city the finest paintings in Spain. P 92-93
Painting in Spain, 1650-1700, from North American collections
    Sullivan, Edward J. and Mallory, Nina A.
Publisher:    The Art Museum, Princeton University in association with Princeton University Press,    
Pub date:    c1982.    

In footnote says the Immaculate Conception painting at the Prado attained the somewhat dubious distinction of fetching the highest price ever paid for a work of art at auction until the recent explosion of the art market in our own century.  It was sold for 615,300 francs in 1852.
From The Catholic Encyclopedia
Article on Bartolomé Esteban Murillo
Online edition found at
Murillo has treated this theme more than twenty times, without repeating himself or ever wearying: six versions at Madrid, six others at Seville, the famous Louvre picture (dated 1678), and still others scattered over Europe -- all these did not exhaust the painter's enthusiasm or his power of expressing apotheosis.
(This encyclopedia was published before the painting went home to Spain)