The Puritans or Pilgrims were a religious group persecuted for their beliefs by England's King James I in the early 17th century.
The Puritans dressed plainly and simply; women weren't to show their cleavage or ankles.
By the 1610s, persecution of the Puritans in England had worsened, and they decided to emigrate from England. They fled first to The Netherlands, where they had some religious freedom, but it was not a place that they could call their own.
So in 1620, a group of Puritans led by Miles Standish et al boarded the famous Mayflower ship and headed for the colonies. They landed at Plymouth, Massachusetts and decided to make it their home. The Puritans endured a horrible winter in 1620-1621, frought with starvation, disease, and death.
As the famous story goes, Native Americans Squanto and Massassoit went to the Puritans' village and offered to them help with their agriculture and home building. Then, in the fall of 1621, a big feast was held to honor their first successful harvest and to thank the Natives for saving them. Thus, the first Thanksgiving was born, a holiday that we have celebrated for centuries.