Jan Hendrik Frederik Grönloh, known as Frits, was born in Amsterdam on June 22, 1882 as the first son of JHF Grönloh and Martha Maria van der Reijden. From this marriage one son and two daughters were born later.
Frits’s father came from a German family who had already settled in the Netherlands in the 18th century. He earned his living as a shopkeeper and blacksmith.
Little is known about Frits’ mother. We do know that young Frits Grönloh had a great admiration for his maternal grandmother, Dina Zoet, whom he knew until he was 11 years old.
She had been a member of the “Zwijndrecht Brotherhood”, a new-lighters movement from the 19th century, and had had a very adventurous life by then standards. According to Nescio, she was once “captive with other new lighters under soldier’s guidance with the barge arrived on the Haarlemmerweg, protected by these soldiers against stone-throwing public.” 
From the age of six to twelve, Frits attended primary school in the lst Swindenstraat in Amsterdam.
Of these six years in his life, we especially remember the walking tours he made on Sunday with his parents in the Amsterdam neighborhood: Watergraafsmeer, Oud-Diemen, Duivendrecht and so many other pieces of nature that he will immortalize in such an inimitable way in his stories. .
Perhaps even more important in connection with his budding love for nature were the Wednesday afternoons on which he set out alone.
By the way, he made notes of these exploration trips in his diary since he was 9 years old, which more or less points to his later writings.
Behind every note, no matter how sober, is the landscape and the emotion about it. Nescio’s prose is unthinkable without those beautiful descriptions of Dutch nature, which he explored throughout his life (the 9-year-old Frits speaks of “the first seizure of these places”  ).
Leaving aside the stories of his grandmother and his diary entries, we know very little about Nescio’s earliest childhood. One of his biographers even mentions that they celebrated at the Grönlohs party when Frits had fallen into the water at the age of 10, because something finally happened to that always so silent boy.