Proto-Indo-European Roots

Root/Stem: *ag'-
Meanings:  to lead, to bring
Hellenic Greek agó 'I lead, I do'
Italic Latin agere 'to lead', Oscan acum 'to lead', Umbrian aitu 'to make move'
Celtic Old Irish ad-aig 'he brings', Welsh & Cornish & Breton a 'he brings', Gaulish amb-actus 'a rider'
Indic Sanskrit ajati 'he makes go'
Iranian  Avestan azaiti 'he makes go'
Armenian Armenian acen 'bring!'
Notes: This root, according to Antoine Meillet, is one of the 'colloquial' Indo-European forms, therefore using*a which was rather rare in Proto-Indo-European. Other linguists often suggest the initial vowel here was the result of mutation of 'laryngeals' *H, which occurred already in the Proto-epoch. 
Anyway, the word reflects the cattle-breeting terminology which could appear only on late stage of the IE development, when hunting was replaced by cattle breeding.