How old was Moses when he parted the Red Sea and how old was he when he wrote the ten commandments I'm trying to write a timeline of Moses's greatest achievements and this is all I haven't found so far. If you know what the two ages of Moses are in relation to these two events, please let me know, that would be great!
According to the Bible, in Exodus 7:7 it states:


  And Moses was eighty years old and Aaron eighty-three years old when
  they spoke to Pharaoh.


Therefore, Moses was at least 80 years old at the red Sea and at Sinai when he received the 10 Commandments from the LORD. To be a bit more specific, it took about 2 months to reach Sinai, but they spent 2 years at Sinai according to Numbers 10:11:


  Now it came to pass on the twentieth day of the second month, in the
  second year, that the cloud was taken up from above the tabernacle of
  the Testimony.


So Moses was 80 or 81 years of age when he reached Sinai and 82 to 83 years of age when they left.