Sister Nivedita wrote of the Swami and Buddha…

That was a great hour indeed, when he spoke of Buddha; for, catching a word that seemed to identify him with its anti-Brahminical spirit, an uncomprehending listener said, “Why Swami, I did not know that you were a Buddhist!”

“‘Madam,” he said rounding on her, his whole face aglow with the inspiration of that name, “I am the servant of the servants of the servants of Buddha. Who was there ever like Him?—the Lord—who never performed one action for Himself—with a heart that embraced the whole world ! So full of pity that He—prince and monk—would give his life to save a little goat! So loving that He sacrificed himself to the hunger of a tigress!—to the hospitality of a pariah and blessed him. And He came into my room when I was a boy and I fell at His feet ! For I knew it was the Lord Himself!”

Many times he spoke of Buddha in this fashion, sometimes at Belur and sometimes afterwards.

(Notes of some wanderings with the Swami Vivekananda by Sister Nivedita)