"him," "her," "them"
Old Spanish gelo. From Vulgar Latin gelo 'id.,' from Latin illi "to him." According to Roberts (2014), Old Spanish g- to Modern Spanish s- under influence from se (1).
Real Academia Española.
Diccionario de la lengua española.
Online. 23rd ed. Madrid: Espasa Calpa.
Roberts, E. A.
A Comprehensive Etymological Dictionary of the Spanish Language with Families of Words based on Indo-European Roots.
2 vols. Xlibris Corporation.