According to Spanish legend, the founding expedition was confronted by a large group of native Tongva peoples whose intention was to drive the strangers away.

[1] Today the 300-year-old work hangs in front of and slightly to the left of the old high altar and reredos in the Mission's sanctuary.

[14] In August 1771, the Portolà expedition, which consisted of "ten Spanish soldiers and two Franciscan priests, encountered armed Tongva Indians on the banks of the Santa Ana River.

The priests chose an alternate site on a fertile plain located directly alongside the Río Hondo in the Whittier Narrows.

[16] The site of the Misión Vieja (or "Old Mission") is located near the intersection of San Gabriel Boulevard and Lincoln Avenue.

[21] In 1776, a flash flood destroyed much of the crops and ruined the original Mission complex, which was subsequently relocated five miles closer to the mountains in present-day San Gabriel (the Tongva settlement of Toviscanga or 'Iisanchanga).

[23] On December 8, 1812 (the "Feast Day of the Immaculate Conception of the Blessed Virgin"), a series of massive earthquakes shook Southern California.

The 1812 San Juan Capistrano earthquake caused the three-bell campanario, located adjacent to the chapel's east façade, to collapse.

[15] A missionary during this period reported that three out of four children died at Mission San Gabriel before reaching the age of 2.

The mission priests established what they thought of as a manual training school: to teach the Indians their style of agriculture, the mechanical arts, and the raising and care of livestock.

"The names of the rancherías associated with San Gabriel Mission were: Acuragna, Alyeupkigna, Awigna, Azucsagna, Cahuenga, Chokishgna, Chowigna, Cucomogna, Hahamogna, Harasgna, Houtgna, Hutucgna, Isanthcogna, Maugna, Nacaugna, Pascegna, Pasinogna, Pimocagna, Pubugna, Sibagna, Sisitcanogna, Sonagna, Suangna, Tibahagna, Toviscanga, Toybipet, Yangna.

"[41] To efficiently manage its extensive lands, Mission San Gabriel established several outlying sub-missions, known as asistencias.

The actor Gil Frye portrayed Father Miguel Sánchez in a 1953 episode, "The Bell of San Gabriel," of the syndicated television anthology series Death Valley Days, hosted by Stanley Andrews.

As a child portrayed in the segment by Peter J. Votrian, Miguel provides funds acquired from a wealthy nobleman to sweeten the tone of the bell at Mission San Gabriel Arcángel.

Years later, the ringing of the bell saves his life when he is a young monk stranded in the desert in the Death Valley country.

[43] A large stone cross stands in the center of the Campo Santo (cemetery), first consecrated in 1778 and then again on January 29, 1939, by the Los Angeles Archbishop John Cantwell.

It serves as the final resting place for some 6,000 "neophytes;" a small stone marker denotes the gravesite of José de los Santos, the last American Indian to be buried on the grounds, at the age of 101 in February 1921.

Buried among the priests is centenarian Eulalia Pérez de Guillén Mariné, the "keeper of the keys" under Spanish rule; her grave is marked by a bench dedicated in her memory, and Victoria Reid, a woman from Comicranga, who was taken to the mission at a young age and became a respected figure in Mexican California.