When he was a hundred and twenty-three years old.

and Aaron is a son of a hundred and twenty and three years in his dying in mount Hor.

Aaron was a hundred and twenty-three years old at the time of his death in Mount Hor.

Eratque Aharon natus centum et viginti tres annos quando mortuus est in Hor monte.

And Aaron was one hundred and twenty three years old when he died in Mount Hor. He was eighty three when he stood before Pharaoh, Exodus 7:7, and forty years he had been with Israel since, which make this number; he was three years older than Moses.