Webster's Revised Unabridged Dictionary · 1913

Gan

Gan , imperfect

[See Gin, v.]

Began; commenced.
This man gan fall (i.e., fell) in great suspicion. — Chaucer
The little coines to their play gunne hie (i. e., hied). — Chaucer
Yet at her speech their rages gan relent. — Spenser

Gan was formerly used with the infinitive to form compound imperfects, as did is now employed. Gan regularly denotes the singular; the plural is usually denoted by gunne or gonne.