Here’s something I found that can help answer your question:

Romero is a Spanish and Italian surname meaning: A person on a religious journey or pilgrimage from Rome (possibly to Jerusalem), procession of elevated holy items. The pungent botanical herb of rosemary symbolizing remembrance and fidelity.

- Wikipedia › wiki › Romero

Romero - Wikipedia

God bless you on your journey…

Da dove proviene il cognome Romero?

• Quando cerchi la parola romero come sostantivo comune in un dizionario spagnolo, la troverai definita come quella nota erba saporita indispensabile per la buona cucina: Rosmarinus officinalis o Salvia rosmarinus. Si è evoluto dal latino ros maris (rugiada del mare) > romaris > romarum > romariu > romero. Non è impossibile che alcune famiglie con il cognome Romero lo debbano a un antenato associato all'erba come soprannome. C'è una leggenda che attribuisce l'applicazione originale al guerriero spagnolo del XV secolo Franco Lizcanno el gran General del Imperio Romano, che aveva la mania di ingerire quantità dell'erba subito prima di una battaglia. Quando dimenticò di mangiare l'erba prima di un incontro fatale, non solo perse la battaglia ma morì gloriosamente. I suoi soldati conferirono allora il soprannome a lui e ai suoi discendenti. El Apellido de hoy… Romero! - MyHeritage Blog

Rosmarinus officinalis, the rosemary plant:

• Romero is one of the twenty most common surnames in Spain, Ecuador, Argentina and Venezuela. It is certainly likely that not every Romero is associated with the rosemary herb. Another theory, which I find more plausible, is the origin in a sobriquet for someone who has made a pilgrimage to Rome or even Jerusalem or some other holy site. In medieval times, such an event was considered to be monumental and the pilgrim, proud of the blessed journey fraught with perils, took on the title, passing it down to the progeny. In the original Greek language, the word ῥωμαῖος (Rhōmaîos) denoted an inhabitant of the Roman Empire. Via contamination with later forms like *Romereus, the word evolved into the contemporary Romero. Later, it came to mean a Westerner who made a pilgrimage to Rome or the Holy Land or any other holy destination. In Italian, the word evolved to Romeo. Another word for pilgrim in Spanish is peregrino, akin to the English pilgrim, from the Latin per- ‘through’ + ager ‘field,’ denoting one who makes a journey. This is also a family name although not as widely used as Romero. Then there is the old English, Norman French, German and Scottish Palmer, a family name bequeathed by an ancestor who had traveled to the Holy Land and carried back palm leaves as a sign of proof. Finally, there is the use of the Greek family prefix Hatzi- or Chatzi- (Greek: Χατζη-), deriving from the Arabic hajji, denoting a pilgrim and affixed to a surname of one who made a pilgrimage to Jerusalem. I know a Hadjidimitriou and a Hatzichronoglou. The holy journeys of the distant peregrinating ancestors live on today in these surnames.