Order of execution of fields and set/get in C#?

I am confused about the order of execution in C# regarding the setting of fields and set/get properties. Why is the value in Test2 not set when the constructor gets called while the value in Test is?

When an instance of a class is created is there some type of hidden/default "constructor" that sets the fields but does not call the setter of properties?

Does the setter get automatically called after the constructor or do I explicitly have to call it?

And finally is there good reasoning for this order of execution?

OUTPUT:

Test: 5
Test2: 0

using System.IO;
using System;

class Program
{
    static void Main()
    {
        Test test = new Test();
        Test2 test2 = new Test2();
    }
}

class Test
{
    private int x = 5;
    public Test(){
        Console.WriteLine("Test: " + x);
    }
}

class Test2
{
    private int _x;
    private int x{
        get
        {
            return _x;
        }
        set
        {
            _x = 5;
        }
    }
    public Test2(){
        Console.WriteLine("Test2: " + x);
    }
}

via Chebli Mohamed