Answer:
Thanksgiving came to be an official holiday in 1863, declared by President Abraham Lincoln.
Step-by-step explanation:
The Thanksgiving feast between Pilgrims and the Natives was not public till Bradford's diary was given to be published in 1789. When, a magazine editor Sarah Josepha Hale came across this tradition celebrated by Pilgrims and Natives, she wrote letters to five Presidents asking to declare Thanksgiving, a national holiday. It was President Abraham Lincoln who paid heed to this request and with an idea of unte the country during his presidency, he declared the last Thursday of November as a Thanksgiving day and declared it a national holiday. The date, however, was changed to fourth Thursday of November by President Franklin D. Roosevelt in 1941, to avoid shifting of national holiday (as some year may have five Thursday's in November).