It is well-known that the present tense of the verb *es- ‘to be’ in the Italic languages shows a mixture of what look as if they were thematic forms (e.g. Old Latin 1 sg. es-om) beside athematic forms (e.g. Latin 3sg. *es-t). A similar state of affairs is attested in the Celtic languages. Within the broader perspective of Indo-European, the thematic forms are puzzling, and efforts have been undertaken to explain them away as secondary. I argue that those efforts have not been successful. By combining the rich but complicated evidence provided by the Celtic languages with the Italic data, it becomes necessary to reconstruct a thematic beside an athematic present of *es- for Italo-Celtic and to hypothesize that the thematic forms were originally used after a focused constituent.