Brookhaven was integrated into the Province of New York following that colony's establishment in 1664, and in 1666 Governor Richard Nicolls granted a patent for the town which confirmed title to the lands purchased. Governor Thomas Dongan issued a patent in 1686 which granted powers to the town and established a representative form of government. The town seal was authorized at this time. The central element of the town seal, the letter “D”, was designated to the Town of Brookhaven as its official cattle earmark by the Duke's Laws of 1665. Although no records exist dating to the town seal's original design plan, it is generally thought that the seal's olive branch signified peace and the whaling tools signified the most lucrative business in the Town of Brookhaven at the time. The current seal is a redesign, retaining the original elements, but adding the Town of Brookhaven and its 1655 date of settlement.