[1][4] Edmund Knox resided next door to the Earl of Limerick, and heard Hayes singing casually in the back garden, and he was greatly impressed by the tone of her voice.

[4] One of the most important events in Hayes' young career occurred early in 1841 when she was invited to sing at another concert in Dublin, sponsored by J.P. Knight at the Long Rooms in Rotunda.

The star of the evening was the celebrated Hungarian virtuoso pianist, Franz Liszt, then only 29 years of age, on his first tour of the British Isles.

Lablache recommended to Sapio that Hayes should study under the foremost singing teacher in Europe, Manuel Garcia, in Paris.

[3] At Milan she became the pupil of Felice Ronconi,[n 3] and through the intervention of Giuseppina Grassini was engaged for the Italian Opera House, Marseilles, where on 10 May 1846 she made her first appearance on the stage as Elvira in I puritani and was enthusiastically applauded.

[2] She remained at Milan during the autumn of 1845 and the carnival of 1846, and took the characters of Lucia di Lammermoor (in which part she became the most sought-after performer of the age),[2] Zora in Mosè in Egitto, Desdemona, and Amina.

Later on in 1846 she sang in Vienna, and on the first night of the carnival of 1847 appeared in Venice in a poor opera composed for her by Malespino, a nobleman, entitled Albergo di Romano.

[4] Under Lumley's management Miss Hayes played Lucia at Her Majesty's Theatre, London, on 2 April 1850, but owing to ill health and other causes she was seldom seen during the remainder of the season.

[4] At the carnival in Rome in 1851 she was engaged at the Teatro d'Apollone, and performed in Maria de Rohan for twelve nights, and received the diploma of the Academia di Santa Cecilia.

[4] From Rome she returned to London, where during the season of 1851 she was the star of the concert-room and of the performances of the Sacred Harmonic Society, singing in the oratorios of Handel, Haydn, and Mendelssohn.

[4] Hayes also performed in Boston, Toronto, Philadelphia, Washington D.C., Charleston, Savannah, New Orleans, and forty-five other locations including the river towns along the Mississippi.

"[1] The newspaper Far West News wrote of her debut at San Francisco's American Theater in 1852 that "[l]ong and loud were the cheers and applause, which greeted her entrée … She acknowledged again and again the enthusiastic testimonial, and again and again the audience cheered and applauded … It was while standing at the foot-lights, amid the storm of applause, that our citizens had the first view of Miss Catherine Hayes … Miss Hayes is about thirty years of age.

The excitement of the audience increased to a furious extent, no doubt with proud ratification that they had heard for once in their lives, the voice that had awakened the admiration of the western world.

[2] Hayes departed California for South America, and after visiting the principal cities (including Lima, Valparaiso, and Santiago) embarked for Australia.

[1] The Age newspaper called Hayes' first concert in the Queen's Theatre,[n 5] Melbourne, "a great event in our local history."

[2] Due to the poor economic situation in Calcutta,[1] she left for Batavia (present-day Jakarta)[4] and Singapore[2] before returning to Australia, where she performed again in Sydney and Melbourne.

[4] She appeared at Jullien's promenade concerts at Her Majesty's Theatre in 1857, when her ballad singing, the branch of art in which lay her greatest power, was much applauded.