What limits does the right to a trial by jury place on the monarch?

it makes trials and court a somewhat equal playing field for the citizens because now the monarch can no longer just throw people in jail on a whim

It prevents the Monarch from choosing the verdict.

Explanation:

The right to a trial by jury, most importantly prevents the Monarch from choosing the verdict. It prevents the king's domination of the courts. It blocades the arbitrary decisions of the king.

The origins of it can be attributed to Magna Carta. Court depends on a body of citizens. Chapter 39 of King John’s Magna Carta guarantees that no free man may suffer punishment without the lawful judgment of his peers.

the group i'm selecting: greeks.

a first group of greek immigrants came to the us in the 1850s. the second group came to america starting in the 1890s due to economic opportunities they didn't have back in their home caused by the hardships of ottoman rule. greek immigration was 90% male, many of them expected to work and return to greece after earning enough capital, but ultimately had to remain in the us after the greek genocide.