England had separated from the Roman Catholic Church under Henry VII in 1534 and Shakespeare wrote Romeo and Juliet in 1597 when tensions between Protestants and Catholics were deep
Friar Lawrence thinks he can use human beings just as he uses herbs, attempting to use Romeo and Juliet to make peace between the Montagues and Capulets
'posion has residence and medicine power' foreshadowing of future events, frair tries to do good by dealing with bad through marrying romeo and juliet to try and fix the family grudge
'virtue itself turns vice' shows how friar deals with humans as if plants