One opportunist who stayed was Octavius Decatur Gass.
( ( One ( opportunist ( who stayed ) ) ) ( ( was ( Octavius ( Decatur Gass ) ) ) . ) )
(ROOT (S (NP (CD One) (NN opportunist) (SBAR (WHNP (WP who)) (S (VP (VBD stayed))))) (VP (VBD was) (NP (NNP Octavius) (NNP Decatur) (NNP Gass))) (. .)))
Octavius Decatur Gass refers to four people. 
( ( Octavius ( Decatur Gass ) ) ( ( refers ( to ( four people ) ) ) . ) )
(ROOT (S (NP (NNP Octavius) (NNP Decatur) (NNP Gass)) (VP (VBZ refers) (PP (TO to) (NP (CD four) (NNS people)))) (. .)))