Learn Spanish (Latin America): El rey antiguo puso el tesoro en la tierra. - The ancient king put the treasure in the ground.

Puso comes from the verb poner (to put). Poner is highly irregular in the preterite (completed past) tense. Instead of using regular endings, its stem changes to pus-, and for the 'he/she/it' form, it takes an -o ending, making it puso.

I thought tierra meant the planet Earth. Can it also mean 'ground'?

Yes! Depending on the context, tierra can mean the planet Earth, land, dirt, soil, or the ground. Here, since the king is putting a treasure into it, 'ground' or 'dirt' is the most natural translation.

Why use the preterite puso here instead of the imperfect ponía?

We use the preterite puso because putting the treasure in the ground is seen as a single, completed event. If the sentence meant the king 'used to put' or 'was putting' the treasure in the ground repeatedly, you would use the imperfect ponía.

Would the meaning change if we put antiguo before rey?

Yes! Placing antiguo after the noun (rey antiguo) focuses on the literal description: a king from ancient times. If you put it before the noun (antiguo rey), it usually translates to 'former king' (someone who used to be king but is not anymore).