Is it farther or further?
Old English tredan (class V strong verb; past tense træd, past participle treden), from Proto-Germanic *tredanan (cf. Old Frisian treda, Middle Dutch treden, Old High German tretan, German treten, Gothic trudan, Old Norse troða).
early 13c., from tread (v.); in reference to automobile tires, it is recorded from 1906.
"that has been stepped on," 1540s, from past participle of tread (v.). The past participle was altered from Middle English treden under influence of Middle English past participles such as stolen from steal.