Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_79 (marriage VARCHAR, became_dauphine VARCHAR)

### Question ###
when was the marriage when became dauphine is 31 august 1412?

### Accurate SQL ###

SELECT marriage FROM table_name_79 WHERE became_dauphine = "31 august 1412"