Many uncertainties plague the early history of the New Kingdom, but it's clear that when Hatshepsut was born, Egyptian power was waxing. Her possible grandfather Ahmose, founder of the 18th dynasty, had driven out the formidable Hyksos invaders who had occupied the northern part of the Nile Valley for two centuries. When Ahmose's son Amenhotep I did not produce a son who lived to succeed him, a redoubtable general known as Thutmose is believed to have been brought into the royal line since he had married a princess.
Hatshepsut was the oldest daughter of Thutmose and his Great Royal Wife, Queen Ahmose, likely a close relative of King Ahmose. But Thutmose also had a son by another queen, and this son, Thutmose II, inherited the crown when his father "rested from life." Adhering to a common method of fortifying the royal lineage—and with none of our modern-day qualms about sleeping with your sister—Thutmose II and Hatshepsut married. They produced one daughter; a minor wife, Isis, would give Thutmose the male heir that Hatshepsut was unable to provide.
Thutmose II did not rule for long, and when he was ushered into the afterlife by what CT scans 3,500 years later would suggest was heart disease, his heir, Thutmose III, was still a young boy. In time-honored fashion, Hatshepsut assumed effective control as the young pharaoh's queen regent.
So began one of the most intriguing periods of ancient Egyptian history.
At first, Hatshepsut acted on her stepson's behalf, careful to respect the conventions under which previous queens had handled political affairs while juvenile offspring learned the ropes. But before long, signs emerged that Hatshepsut's regency would be different. Early reliefs show her performing kingly functions such as making offerings to the gods and ordering up obelisks from red granite quarries at Aswan. After just a few years she had assumed the role of "king" of Egypt, supreme power in the land. Her stepson—who by then may have been fully capable of assuming the throne—was relegated to second-in-command. Hatshepsut proceeded to rule for a total of 21 years.