Antonija Meldere-Millere was born on 13 October 1876 in Jumpravmuižā, Governorate of Livonia, Russian Empire[1][2] to Miķeļis and Matilde (née Flintman) Millere-Meldere.

[1] During her schooldays at Lomonosov, she developed a friendship with Fēlikss Lūkins [lv], whom she would later marry[2] and published her first novel, Trīs jaungada naktis (Three New Year's Nights) in 1892.

Taking advantage of the museums and art galleries, she supplemented her knowledge and learned English, French, German, Italian, Latin and Russian.

The book dealt with marital dissatisfaction and free love, and caused a stir for its controversial depiction of female sexual liberation.

She published other articles on themes about civic, political and social issues affecting women in journals such as Dzimtenes Vēstnesis (Homeland Gazette) and Latviešu izglītības biedrības gadagrāmata (The Almanac of the Latvian Educational Association).

[5] During World War I, Kaija's husband was called up to serve as a surgeon and the family followed him to posts in the Crimea, Moscow and Petrograd.

[5] Kaija called upon women to donate jewelry, silverware, and other tangible assets which were deposited, and after the war became the gold reserve of the government.

[1] Beginning in 1920, Kaija worked in the Foreign Office of the Republic of Latvia, as a French press commentator and was head of the art and literature department of Latvijas Sargs (Latvian Guard).

A few months later in Valmiera, Kaija gave a rare speech, which she did not often do because of her hearing difficulty, on social issues facing the nation.