The Midrash, at the start of Parshat VaYehi (בראשית רבה,פרשה צ"ו ד"ה(א)ויחי ), states that the servitude in Egypt began with Jacob's death (כיוון שנפטר יעקב אבינו התחיל שעבוד מצרים על ישראל).
When I learned this passage with my son, Ariel, he cogently objected that the servitude only began two hundred and ten years later, at the start of Sefer Shemot!
After discussing the matter, we came up with the following.
Rashi (Ex. 1, 8), cites the famous dispute between Rav and Shmuel (BT Sota 11a) regarding the words 'a new king arose in Egypt.' One understood this to refer literally to a new king (or, a new royal dynasty). The other claimed that it referred to the same Pharaoh that Joseph served, whose policy changed (נתחדשו גזירותיו). Now, I had always had trouble understanding the second opinion.
What happened to make the same Pharaoh, who was so impressed with Jacob and so supportive of Joseph, change his policy toward the Israelites from one of beneficence to one of servitude and persecution?
Following a line of analysis set out by the Rav זצ"ל, Ariel noted that Pharaoh's admiration for Jacob is actually a natural point of departure. The Midrash, Ariel observed, shows that when Jacob died Pharaoh saw his opportunity to transform the Israelites into Egyptians, with himself as their god-king. Jacob's passing signalled the end of the old world, of the tradition of Abraham. Now, the Israelites could shed their Canaanite trappings and become Egyptians. Notice, that according to the story of Jacob's funeral, the Egyptians tried to turn it into a national day of Egyptian mourning (Gen.50, 7-11):
And Joseph went up to bury his father; and with him went up all the servants of Pharaoh, the elders of his house, and all the elders of the land of Egypt, and all the house of Joseph, and his brethren, and his father's house; only their little ones, and their flocks, and their herds, did they leave in the land of Goshen. And there went up with him both chariots and horsemen; and it was a very great company. And they came to the threshing-floor of Atad, which is beyond the Jordan, and there they wailed with a very great and sore wailing; and he made a seven day period of mourning for his father. And when the inhabitants of the land, the Canaanites, saw the mourning in the floor of Atad, they said: 'This is a grievous mourning for the Egyptians.'
The Israelites, however, did not cooperate. They, in large part, refused to play along. They buried Jacob on their own and continued to observe the covenant of Abraham (though Hazal are divided as to the extent).
Feeling spurned, Pharaoh reversed his pro-Israelite policy and, instead, determined to grind them into the dust from which they had come.