Bjorn Tyrelle Olsen or Grandpa Olsen is or was the father of Mona Simpson and the husband of Linnea Penelope. He is the maternal grandfather of Homer Simpson, the paternal great-grandfather of Bart Simpson, Lisa Simpson, and Maggie Simpson, and also the grandfather-in-law of Marge Simpson. He was an entrepreneur form Scandinavia who moved to the US to try to get better business with his family. He did not approve of Mona's relationship with Abe. He was thought to be still alive by his grandson Homer but that is unclear.
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