An old, old, old, word – even had a past participle flogen back in the day. The etymological entry and the forms are, um, measurably a good 20 minute dive into the OED.

“flee, v.” OED Online, Oxford University Press, June 2020, http://www.oed.com/view/Entry/71387. Accessed 7 August 2020.

• 1.081 They fled their hall to dying fall
• 4.037 and the goblin soldiers fled
• 6.065 and they fled off down the slopes crying
• 6.070 and fled into the forest
• 12.017 Then Bilbo fled.
• 12.078 and fled up the tunnel.
• 12.101 They fled further down the tunnel
• 13.043 that fled from the approach of their torches
• 17.048 and fled to either side.
• 17.050 and each flickered as it fled as if with stinging fire.
• 17.056 and rider fell or fled before them.
• 18.024 and they fled
• 18.024 and such as fled south or west
• 19.044 and fled with it,