At first, life was very hard for the Plymouth pilgrims. After establishing their colony, they had to struggle with all kinds of problems such as contagious diseases, ice cold winters, and ruined harvests. Thankfully, members of the Wampanoag, a local Native-American tribe, were on hand to teach the pilgrims important life-skills such as cultivating corn, which helped them adapt to their new environment.
It was largely due to the assistance of the Wampanoag that the pilgrims were able to enjoy their first successful harvest in 1621. To celebrate this momentous event, the colony's governor William Bradford organized a huge feast, which was attended by representatives of the local native tribes who'd been so helpful, and with whom the settlers had forged such amicable relations. This feast has gone down in history as the first Thanksgiving Day. And though it has been celebrated in the United States ever since, it was only officially declared a public holiday in 1863, at the height of the Civil War, when Abraham Lincoln asked his fellow Americans to "commend to his tender care all those who have become widows, orphans, mourners or sufferers in the lamentable civil strife" and to "heal the wounds of the nation."