when was lawrence academy at groton established? 
CREATE TABLE table_2439728_1 (founded INTEGER, school VARCHAR)
SELECT MIN(founded) FROM table_2439728_1 WHERE school = "Lawrence Academy at Groton"
### Context: CREATE TABLE table_2439728_1 (founded INTEGER, school VARCHAR) ### Question: when was lawrence academy at groton established?  ### Answer: SELECT MIN(founded) FROM table_2439728_1 WHERE school = "Lawrence Academy at Groton"