Who said "Constancy in friendship is a rare thing to find."?

This quote is attributed to Petrarch.

Constancy in friendship is a rare thing to find. - Petrarch

"Constancy in friendship is a rare thing to find."

Petrarch Friendship

Poet Philosopher Italian 1304–1374

"To be everywhere is to be nowhere."

"Five centuries have passed since my birth, yet my heart still beats with the same passions."

"Love is the only thing that makes life worth living."

"The greatest wealth is a poverty of desires."

"Friendship is built on trust and honesty."

"True friendship is worth more than gold."

"Good friends are like stars, always there even when you can't see them."

"Friendship means sacrifice."