If you feel like you’ve been hearing a lot about parishes celebrating 100th anniversaries lately, it’s because you have.

According to “A History of the Parishes of the Archdiocese of Chicago,” a dozen parishes were founded in 1916. Five of them — St. Barbara, Brookfield; St. Constance; St. Sabina; St. Thomas of Canterbury; and St. William — had their official anniversary Masses this month.

And while 1916 was a big year for opening parishes, it was also the harbinger of a generation of growth in the archdiocese.

So what happened in 1916?

The easy answer is the installation of George Mundelein as archbishop on Feb. 9 of that year. Archbishop Mundelein, who would become the first ordinary to be a cardinal in 1924, presided over the creation of about 80 parishes during his 23-year tenure.

But Chicago historian Ellen Skerrett said that doesn’t tell the whole story. Part of the credit should go to Cardinal Mundelein’s predecessor, Archbishop James Quigley.

“It was around 1909 that he started dividing the old parishes into the mile-square parish,” Skerrett said, starting the pattern in which generations of Chicagoans — Catholics and non-Catholics alike — identified their neighborhoods by parish.

“I would argue that it’s one the most brilliant things the archdiocese ever did,” said Skerrett, who is now working on the Jane Addams Papers Project at Ramapo College of New Jersey. “These were walking neighborhoods, and if you think of a mile square, no one had to walk more than four blocks to get to the parish, and, just as important, the school.”

If the plan started under Archbishop Quigley, Cardinal Mundelein ran with it, seeking to unite different ethnic groups that previously had each worshipped in their own churches.

Not every mile-square church has remained open, Skerrett said, and those that have often can point to strong leadership at key points of their history.

For example, St. Sabina, 1210 W. 78th Place, and neighboring St. Justin Martyr were both founded in 1916. St. Justin Martyr closed in 1989, while St. Sabina has become one of the best-known predominantly African-American parishes in the city.

Some of that is due to its early leadership, with pastor Father Thomas Egan persuading parishioners to build the large Tudor gothic church — the second church the parish built in 20 years — and its community center during the Depression, when material and labor costs were lower, Skerrett said.

State Sen. Jacqueline Collins, a longtime parishioner at St. Sabina, wrote the parish history for the anniversary book St. Sabina distributed at its Oct. 2 celebration.

The families that worship at St. Sabina now — mostly but not exclusively African- American — feel a kinship with the Irish Catholics that sacrificed to build the parish up at its beginnings.

“So much of the Irish tradition and culture transfers to our experience as African- Americans,” Collins said. “They were centered on faith and family, and their work ethic and their sacrifice and dedication … that all transfers.”

Indeed, when St. Sabina was threatened with closure in the early 1980s, Father Michael Pfleger, then the pastor, as he is today, led the congregation in its efforts to pay off its debts and cement its place as an integral part of its community. The parish paid off its debt to the archdiocese in 1990 and has remained financially self-sufficient since.

“The congregation is very proud of where we are and what we have done over the years,” Collins said.

St. Thomas of Canterbury, 4827 N. Kenmore Ave., has also seen a dramatic change in its neighborhood since it was founded.

It was the first of three parishes organized by then-Archbishop Mundelein in March 1916 after a group of Catholic lay people petitioned for their own parish because they were unable to get to Our Lady of Lourdes Parish, now at 4640 N. Ashland, and St. Ita, 1220 W. Catalpa.

At the time, the neighborhood around St. Thomas was affluent, said Franciscan Father Paul Schneider, the pastor of the parish. It was also a mix of various European nationalities, giving the parish the American flavor that Mundelein wanted.

The socioeconomic status of the parish changed in the ensuing decade, and in 1971, Uptown was being called the most dangerous neighborhood in the country. To respond to waves of new residents — from Appalachia, from Latin America, from Vietnam — the parish developed a variety of outreach programs, including a soup kitchen that still serves 150 people two evenings a week. That’s down from 900 served twice a week in the 1980s. In 1979, U.S. Catholic profiled the parish under the headline, “The Parish Speaks Five Languages.”

It still does, with regularly scheduled Masses in Spanish, Vietnamese, Laotian and Eritrean, as well as English. All those languages were planned to be part of the centennial Mass Oct. 16, along with petitions in Tagalog and Igbo.

Schneider said his parishioners find commonality in their diversity.

“They all went through struggles to get here,” Schneider said. “Everybody here focuses on their belief in Jesus Christ, and we’re able to come together and pray to God.

St. Constance Church, 5843 W. Strong Ave., was an exception to then-Archbishop Mundelein’s plan to build blended rather than ethnic parishes. St. Constance was formed to serve Polish families on the Northwest Side in response to a request from 90 Polish families that belonged to Our Lady of Victory Parish.

The parish to this day maintains a strong Polish identity, with three Sunday Masses and a daily Mass in Polish. The Polonia Club — the original group that asked for a Polish parish, still exists and is going strong. It celebrates its centennial with a Mass Oct. 16.

St. Barbara Parish in Brookfield actually started in 1912 as a mission of St. Francis Xavier Church in LaGrange. It received the status of a parish in 1916, and grew along with the community of Brookfield. Membership in the new parish, which celebrates is centennial Mass Oct. 16, increased rapidly, according to “A History of the Parishes of the Archdiocese of Chicago,” with membership increasing from 118 families in 1920 to 300 families in 1923.

That was the same year the parish began construction on its second church, knocking down the first church as using the space as a parking lot when people began driving to church. Its current church, built to accommodate a growing post-war population, was dedicated in 1966.

Father Edgar Rodriguez, the parish’s administrator, said the people of the parish are open and welcoming.

“I just got here in July, and the people are very friendly,” Rodriguez said. “They are very open to help the poor. There a real missionary spirit here. We are smaller, about 800 people, but we are a pretty active 800 with good turnout for the activities we do.”

St. William Parish, 2600 N. Sayre Ave., celebrated its centennial on Oct. 2. When it was formed, it was so far from the center of the city when it was instituted that its boundaries took in far more than a square mile. Land for the church was purchased by the pastor of St. Pascal Parish with the intent that a parish be formed to serve German- and English-speaking Catholics in the area, and the first Mass in St. William’s frame church was celebrated on Christmas 1915. The first pastor of St. William, Father Francis Epstein, was appointed in May 1916.

Over the next 15 years, St. William’s area was reduced by the creation of St. Priscilla; St. Celestine, Elmwood Park; St. Giles, Oak Park; and St. Ferdinand.