The word “dial” comes from the Latin word “dialis”, which means “daily”, because a sundial throws a shadow related to the time of day.
The word “dialling” originally referred to the math required to create a sundial to tell time based on the position of the sun, and those skilled in the art were called dialists.
The word “dial” was also referred to the gear in a medieval clock which turned once per day.
The original dial telephone sent out a signal “click” for each number dialed.
One click for 1, two “clicks” for 2, etc. The zero was reserved for the operator.
“One” was never used because early switching systems read every signal as beginning with one click, regardless of the number you were dialling.
So technically, no phone number could start with 1.