Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_55 (birth VARCHAR, spouse VARCHAR, became_consort VARCHAR)
### Question:
Name the birth of the person that has a spouse of frederick iv and became consort of 4 april 1721
### Answer:
SELECT birth FROM table_name_55 WHERE spouse = "frederick iv" AND became_consort = "4 april 1721"