Can't load basic ContentPage - XamlParseException "No Property of name Id found"

So I'm trying to get this app off the ground so I can actually start putting functionality in it and it's failing to load the first page.

I'm getting a XamlParseException when it attempts to LoadFromXaml in the generated class.

Error message is "No Property of name Id found"

 public partial class ProxDefaultPage : ContentPage {//This is a generated class

     private ActivityIndicator Discoverying;

     private void InitializeComponent() {
         this.LoadFromXaml(typeof(ProxDefaultPage));//error thrown here
         Discoverying = this.FindByName<ActivityIndicator>("Discoverying");
     }
 }

Here's the XAML markup of the page in question

  <?xml version="1.0" encoding="UTF-8"?>
  <ContentPage
      Id     ="cpDiscovery"
      x:Name ="Discovery"
      xmlns ="http://xamarin.com/schemas/2014/forms"
      xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
      x:Class="MyApp.Droid.DefaultPage">
          <ActivityIndicator
              Id       ="aiDiscovering"
              IsRunning="true"
              Color    ="Blue"
              x:Name   ="Discoverying" />
  </ContentPage>

What am I missing in the markup that isn't getting parsed?

This is using Xamarin Forms on an Android project.