function ConvertTo-RomanNumeral
{
  <#
    .SYNOPSIS
        Converts a number to a Roman numeral.
    .DESCRIPTION
        Converts a number - in the range of 1 to 3,999 - to a Roman numeral.
    .PARAMETER Number
        An integer in the range 1 to 3,999.
    .INPUTS
        System.Int32
    .OUTPUTS
        System.String
    .EXAMPLE
        ConvertTo-RomanNumeral -Number (Get-Date).Year
    .EXAMPLE
        (Get-Date).Year | ConvertTo-RomanNumeral
  #>
    [CmdletBinding()]
    [OutputType([string])]
    Param
    (
        [Parameter(Mandatory=$true,
                   HelpMessage="Enter an integer in the range 1 to 3,999",
                   ValueFromPipeline=$true,
                   Position=0)]
        [ValidateRange(1,3999)]
        [int]
        $Number
    )

    Begin
    {
        $DecimalToRoman = @{
            Thousands = "","M","MM","MMM"
            Hundreds  = "","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"
            Tens      = "","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"
            Ones      = "","I","II","III","IV","V","VI","VII","VIII","IX"
        }

        $column = @{
            Thousands = 0
            Hundreds  = 1
            Tens      = 2
            Ones      = 3
        }
    }
    Process
    {
        [int[]]$digits = $Number.ToString().PadLeft(4,"0").ToCharArray() |
                            ForEach-Object { [Char]::GetNumericValue($_) }

        $RomanNumeral  = ""
        $RomanNumeral += $DecimalToRoman.Thousands[$digits[$column.Thousands]]
        $RomanNumeral += $DecimalToRoman.Hundreds[$digits[$column.Hundreds]]
        $RomanNumeral += $DecimalToRoman.Tens[$digits[$column.Tens]]
        $RomanNumeral += $DecimalToRoman.Ones[$digits[$column.Ones]]

        $RomanNumeral
    }
}