Part A:

Erant ôlim in Thessaliâ duô frâtrês,

There were once two brothers in Thessaly,

quôrum alter Aesôn, alter Peliâs appellâbâtur.

of which one was called Aeson, the other (was) Pelias.

Aesôn prîmô rêgnum obtinuerat;

Aeson at first had held the power;

at post paucôs annôs Peliâs rêgnî cupiditâte adductus nôn modo frâtrem suum expulit,

but after a few years Pelias, influenced by a desire for power, not only drove out his brother,

sed etiam in animô habêbat Iâsonem, Aesonis fîlium, interficere.

but also decided to kill Jason, the son of Aeson.

Part B:

Quîdam tamen amicî Aesonis puerum ê tantô perîculô êripere cônstituêrunt.

However/neverthelss certain friends of Aeson decided/established to save the boy from such great danger.

Noctû igitur Iâsonem ex urbe abstulêrunt,

At night therefore they carried Jason out of the city,

et cum posterô diê ad rêgem rediissent

and when they had returned to the king (on) the next day

eî renûntiâvêrunt puerum mortuum esse

they reported to him that the boy was dead.