While living in Padua, Galileo began a relationship with Marina Gamba, a Venetian woman. They never married but had three children together.

Galileo and Marina Gamba's first daughter, Virginia, was born. Virginia (later Sister Maria Celeste) became a devoted daughter and source of support for Galileo.

Galileo and Marina Gamba's second daughter, Livia (later Sister Arcangela) was born. Livia did not have as close a relationship to Galileo as Virginia.

Galileo and Marina Gamba's son, Vincenzo, was born. He was later legitimized by the Grand Duke Cosimo II.

Galileo placed his daughters, Virginia and Livia, in the Convent of San Matteo in Arcetri. Because they were illegitimate, he felt their prospects for marriage were limited. They lived out their lives as nuns.

Although the circumstances are unknown, Galileo ended his relationship with Marina Gamba when he moved to Florence.

Galileo maintained extensive correspondence with leading intellectuals, scientists, and patrons across Europe, exchanging ideas, sharing his discoveries, and debating scientific concepts. His letters provide valuable insights into his thinking and the scientific landscape of the time.