Simplify the following text for a Grade 11 native English-speaking person.
Original: From 1801 , in order to symbolise the union of the Kingdom of Great Britain with the Kingdom of Ireland a new design , which included the St Patrick 's Cross , was adopted for the flag of the United Kingdom of Great Britain and Ireland .
Simplified: From 1801 , in order to symbolise the union of the Kingdom of Great Britain with the Kingdom of Ireland , a new design was adopted for the flag of the United Kingdom of Great Britain and Ireland .