Who are Ragnar's sons and wives, and how close is he to them?

^{I haven't seen Vikings past season 3, the data comes from the Wiki}

According to the "Vikings Wiki", Ragnar Lothbrok, not counting possible bastards had 6 children with two wives:

Initially, he was married to shield-maiden Lagertha that had two children:

• Gyda Ragnarsdottir :

Born in 779, Ragnar's firstborn and the only daughter (and arguably the most loved child).

She died at the age of 14 as a victim of a plague

• Bjorn Ragnarsson/ Bjorn Ironside

Born in 781. While indeed it is revealed that his father might be in fact Rolo (Ragnar's brother), Ragnar always has been treating him as his own and Bjorn has always called Rangar his father, whom he deeply loved and admired.

After Gyda's death and Lagertha's miscarriage, Ragnar is convinced that it was a sign from the goddess Freyja that he should look for another wife. Still, he remains quite fond of Lagertha and Bjorn. He eventually marries Götaland princess Aslaug, who promised to give him many sons:

• Ubbe Ragnarsson :

Born in 795. While technically born out of wedlock (Ragnar was still married to Lagertha), he has been legitimized and turned into Ragnar's heir. He is the most mellow of his surviving children and has the closest resemblance to the young Ragnar.

• Hvitserk Ragnarsson :

Born in 797. He resents his father for his long absence and promises to kill him given a first chance. However, when Ragnar challenges his sons to kill him, he refuses.

• Sigurd "Snake-in-the-eye" Ragnarsson :

Born in 798. He is deeply resentful towards his mother and younger brother Ivar.

This culminates in an argument that leads to Ivar killing his brother.

• Ivar "The Boneless" Ragnarsson :

Born in 800 AD as the youngest son of Ragnar. He was born deformed with twisted legs and weak bones and that caused him to be resentful towards his brother. This, and overly protective treatment received from his mother has turned him into a bitter, cruel person.