Of Plymouth Plantation is significant because it chronicles facts about the establishment of the Pilgrim Church in England, the group who left for Holland and eventually the trip on the Mayflower to the New World on November 11, 1620, and the early days of colonial America. Bradford was governor of the colony for 33 years. Among many things he writes about, maybe the most famous is the first Thanksgiving.
It is also significant because it is the most lucidly reliable account of those early days in American history. One of the lessons about the Puritans in reference to their common beliefs or personalities is that they came to the New World seeking religious freedom. Bradford's work draws on many Biblical parallels. They wanted to "purify" (hence the name "Puritans") the Church of England, believing that the Protestant Reformation did not go far enough in attempting this. It also seems that their fervor for this purification in the new community in the new world eventually declined; it was said that Bradford wrote some of this text with a nostalgia, implying that their focus on their role as religious crusaders/founders of a new world gave way to expansion and maybe more focus on other aspects of life.
Of Plymouth Plantation, begun in 1630, is significant because it is one of the first histories of the Puritans who voyaged to America. Though it goes back to record facts about the group's time in the Netherlands, much of it is a first-person account of what life was like in America in the earliest days of the young colony. Historians find it a useful corrective to later myths that arose about these first settlers.
The plain and simple language of the narrative reflects the emphasis the Puritans placed on plain and simple lives. Bradford, first governor of the colony, believed in plain living, for he feared that too much material prosperity would divert people's attention from God. We learn that the Puritans were a deeply religious people who believed that God's providence kept them alive at crucial junctures, and that God would intervene to punish people who were proud and profane. At the same time, the book is written not entirely as a religious narrative but as a historical account of the group's move to the New World.
The Puritans and especially Bradford, come across as having gentle and humane personalities, and as less punitive and judgmental than their counterparts in the Massachusetts Bay Colony. For example, when Roger Williams was exiled for his religious believes, Bradford wrote:
He is to be pitied and prayed for; and so I shall leave the matter and desire the Lord to show him his errors and reduce him into the way of truth.