19 Domestication of the watermelon (Citrullus lanatus) has alternatively been placed in South 20 Africa, the Nile valley, or more recently West Africa, with the oldest archeological evidence 21 coming from Libya and Egypt. The geographic origin and domestication of watermelons has 22 therefore remained unclear. Using extensive nuclear and plastid genomic data from a 3,560-23 year-old Citrullus leaf from a mummy's sarcophagus and skimmed genomes for 24 representatives of the seven extant species of Citrullus, we show that modern cultivars and the 25 ancient plant uniquely share mutations in a lycopene metabolism gene (LYCB) affecting pulp 26 color and a stop codon in a transcription factor regulating bitter cucurbitacin compounds. This 27 implies that the plant we sequenced had red-fleshed and sweet fruits and that New Kingdom 28 Egyptians were cultivating domesticated watermelons. The genomic data also identify extant 29 Sudanese watermelons with white, sweet pulp as the closest relatives of domesticated 30 watermelons. 31 32 Archaeogenomics | plant domestication | ancient plant genome | Africa | New Kingdom Egypt 33 | Pharaonic tomb 34 35 Significance statement [120 words] 36 With some 197.8 million tons in 2017, watermelon, Citrullus lanatus, is among the World's 37 most important crops, yet its area of origin and domestication have remained unclear, with 38 competing hypotheses favoring South Africa, West Africa, Central Africa, or the Nile valley. 39 We generated extensive nuclear and plastid genomic data from a 3500-year-old leaf from a 40 Pharaonic sarcophagus and performed genome skimming for representatives of all other 41 Citrullus species to compare key genes involved in fruit bitterness and color. White-fleshed, 42 non-bitter melons from southern Sudan are the closest relatives of domesticated watermelon, 43 and the ancient genome shares unique alleles with a red-fleshed, non-bitter domesticated form 44 (but no wild forms), implying that 18 th Dynasty Egyptians were cultivating domesticated 45 watermelon by 3500 years ago. 46