Both Uses of

summon

in

The Narrative of the Life of Frederick Douglass

They find less difficulty from the want of beds, than from the want of time to sleep; for when their day's work in the field is done, the most of them having their washing, mending, and cooking to do, and having few or none of the ordinary facilities for doing either of these, very many of their sleeping hours are consumed in preparing for the field the coming day; and when this is done, old and young, male and female, married and single, drop down side by side, on one common bed,—the cold, damp floor,—each covering himself or herself with their miserable blankets; and here they sleep till they are summoned to the field by the driver's horn.†
Chpt 2

summoned = called forth; or called to come

There must be no halting; every one must be at his or her post; and woe betides them who hear not this morning summons to the field; for if they are not awakened by the sense of hearing, they are by the sense of feeling: no age nor sex finds any favor.†
Chpt 2 *

summons = calls forth; or a document calling to come

Definition:

to call forth

The exact meaning of summon can depend upon its context. For example:

"summon to court" -- officially demand that someone appear in court (call them to court)
"summon the team to a meeting" -- call upon the team members to attend a meeting
"summon help" -- call others to come and help
"summon her courage" -- call forth her courage from within