Verbs ser (to be), estar (to be), and tener (to have) in the past tense (pretérito perfecto)

Ser, past tense

Yo fui

Tú fuiste

Él/Ella/Usted fue

Nosotros/as fuimos

Vosotros/as fuisteis

Ellos/Ellas/Ustedes fueron

Estar, past tense

Yo estuve

Tú estuviste

Él/Ella/Usted estuvo

Nosotros/as estuvimos

Vosotros/as estuvisteis

Ellos/Ellas/Ustedes estuvieron

Tener, past tense

Yo tuve

Tú tuviste

Él/Ella/Usted tuvo

Nosotros/as tuvimos

Vosotros/as tuvisteis

Ellos/Ellas/Ustedes tuvieron

Note how ser is, in this tense, identical to ir. Spanish developed from Vulgar Latin, which was brought to the Iberian Peninsula by the Roman soldiers during the Second Punic War (3rd Century BC). In Classical Latin, the equivalent verbs for ser and ir (esse and ire, respectively) did have different past tenses, but Spanish, as it developed from a not-so-well-spoken version of the ancient language, “took” the Latin past tense for esse (ser) and applied it to both verbs ser and ir, ignoring the “original” Latin past tense for ire.