All 3 Uses

summon
in
King Lear
(Auto-generated)

Deliver'd letters, spite of intermission, Which presently they read: on whose contents, They summon'd up their meiny, straight took horse;†
Scene 2.4

summon'd = called forth; or called to come
Tremble, thou wretch, That hast within thee undivulged crimes Unwhipp'd of justice: hide thee, thou bloody hand; Thou perjur'd, and thou simular man of virtue That art incestuous: caitiff, to pieces shake That under covert and convenient seeming Hast practis'd on man's life: close pent-up guilts, Rive your concealing continents, and cry These dreadful summoners grace.†
Scene 3.2
and why you answer This present summons?†
Scene 5.2 *

summons = calls forth; or a document calling to come

Definitions:

(1) (summon)
to call to appear, come, or take action -- often used for official or serious situations, including legal notices or emotional/spiritual urges
(2) (meaning too rare to warrant focus)