Simplify the following text for a Grade 13 native English-speaking person.
Original: These people first began to occupy Ireland in large numbers with the Plantation of Ulster , a planned process of colonization which took place under the auspices of James VI of Scotland and I of England on land confiscated from the Irish nobility , most extensively in the Province of Ulster .
Simplified: These people first began to occupy Ireland in large numbers with the Plantation of Ulster , ordered by James I of England on land taken from the Irish nobility , mostly in the Province of Ulster .