When was the oldest mythic card released and what are its legal play formats?
the oldest card refers to MIN(originalReleaseDate); mythic card refers to rarity = 'mythic'; legal play refers to status = 'legal'; play format refers to format
SELECT T1.originalReleaseDate, T2.format FROM cards AS T1 INNER JOIN legalities AS T2 ON T1.uuid = T2.uuid WHERE T1.rarity = 'mythic' AND T1.originalReleaseDate IS NOT NULL AND T2.status = 'Legal' ORDER BY T1.originalReleaseDate LIMIT 1