[JupiterMoon]

Fortran indexes from 1. Fortran is the original higher than assembly level scientific computing language and a lot of scientists alive today got their first programming experience in Fortran. I suspect that they all follow from Fortran.

[sampo]

Fortran also gives you the option to define any starting index, when you declare an array. (Even negative.)

But it's true, indexing from 1 is common, or idiomatic, in Fortran.