The family cemetery, El Campo Santo, was established in the 1850s. The earliest documented date is the burial of founder William Workman's brother, David, in November 1855. A year later, artist Henry Miller, touring California to visit and sketch the Spanish and Mexican-era Roman Catholic missions, stayed at the Workman House and prepared sketches for a chapel contemplated by Workman. On 30 May 1857, the cornerstone to St. Nicholas' Chapel (named in honor of Workman's wife, Nicolasa Urioste de Valencia) was laid and blessed by Bishop Thaddeus Amat. Construction of the Gothic Revival structure, which measured 24' x 48' and featured gilt ceilings and stained glass windows, was completed by the early 1860s. The cemetery was used exclusively as a private burial ground for Workman and Temple family members and friends and masses were regularly heard, presumably by a priest visiting from Mission San Gabriel, at the chapel.