Compare with an almost identical version at Christie's, Rome, 4 Dec. 1991, lot 83; both compositions appear to be preparatory sketches for Lama's larger vertical picture of the same subject in the Kunsthistorisches Museum, Vienna (N. Spinosa, Pittura Napoletana del Settecento dal Barocco al Rococò, Naples, 1986, p. 139, no. 151 and p. 273, fig. 174)