Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Name | Birth | Marriage | Became Dauphine | Ceased to be Dauphine | Death | Husband |
| --- | --- | --- | --- | --- | --- | --- |
| Joan of Bourbon | 3 February 1338 | 8 April 1350 | 22 August 1350 husband became the Dauphin | 8 April 1364 became Queen | 6 February 1378 | Charles, 1st Dauphin |
| Margaret of Burgundy | 1393 | 31 August 1412 | 31 August 1412 | 18 December 1415 husband's death | 2 February 1441 | Louis, 6th Dauphin |
| Jacqueline, Countess of Hainaut | 16 August 1401 | 6 August 1415 | 18 December 1415 husband became the Dauphin | 4 April 1417 husband's death | 8 October 1436 | John, 7th Dauphin |
| Margaret Stewart of Scotland | 25 December 1424 | 24 June 1436 | 24 June 1436 | 16 August 1445 | 16 August 1445 | Louis, 9th Dauphin |
| Charlotte of Savoy | 11 November 1443/5 | 14 February 1451 | 14 February 1451 | 22 July 1461 became Queen | 1 December 1483 | Louis, 9th Dauphin |
| Catherine de' Medici | 13 April 1519 | 28 October 1533 | 10 August 1536 husband became the Dauphin | 31 March 1547 became Queen | 5 January 1589 | Henry, 16th Dauphin |
| Mary, Queen of Scots | 8 December 1542 | 24 April 1558 | 24 April 1558 | 10 July 1559 became Queen | 8 February 1587 | Francis, 17th Dauphin |
Question:
when was the marriage when became dauphine is 31 august 1412?
Answer:
31 August 1412