On what date did the woman married to Louis II become consort?
CREATE TABLE "princely_consort_of_monaco" (
  "name" text,
  "birth" text,
  "marriage" text,
  "became_consort" text,
  "ceased_to_be_consort" text,
  "spouse" text
);
SELECT "became_consort" FROM "princely_consort_of_monaco" WHERE "spouse"='louis ii';